Preoperative fasting for preventing perioperative complications in children

Preoperative fasting for preventing perioperative

complications in children (Review)

Brady M, Kinn S, O’Rourke K, Randhawa N, Stuart P

This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library2005, Issue 4

http://www.thecochranelibrary.com

1Preoperative fasting for preventing perioperative complications in children (Review)

Copyright ©2005 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd

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T A B L E O F C O N T E N T S

1ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2SYNOPSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4CRITERIA FOR CONSIDERING STUDIES FOR THIS REVIEW . . . . . . . . . . . . . . . . . .

4SEARCH STRATEGY FOR IDENTIFICATION OF STUDIES . . . . . . . . . . . . . . . . . . . .

5METHODS OF THE REVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6DESCRIPTION OF STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7METHODOLOGICAL QUALITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

28AUTHORS’ CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29POTENTIAL CONFLICT OF INTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . .

29ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30SOURCES OF SUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35Characteristics of included studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

47Characteristics of excluded studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

47ADDITIONAL TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

47Table 01. Guidelines for Paediatric Preoperative Fasting . . . . . . . . . . . . . . . . . . . . .

48Table 02. The ASA Physical Status Classification System . . . . . . . . . . . . . . . . . . . . .

49Table 03. Search strategy for electronic databases . . . . . . . . . . . . . . . . . . . . . . . .

54Table 04. Participants’ Age and Paediatric Age Groups . . . . . . . . . . . . . . . . . . . . . .

54Table 05. Details of Quality Evaluation by Trial . . . . . . . . . . . . . . . . . . . . . . . .

59Table 06. Summary Statistics - Gastric Volume (ml/kg) - Intervention Groups . . . . . . . . . . . . . .

61Table 07. Summary Statistics - Gastric Volume (ml/kg) - Control Group . . . . . . . . . . . . . . . .

63Table 08. Summary Statistics - Gastric pH - Intervention Groups . . . . . . . . . . . . . . . . . .

66Table 09. Summary Statistics - Gastric pH - Control Group . . . . . . . . . . . . . . . . . . . .

69Table 10. Key to Secondary Outcome Data Tables . . . . . . . . . . . . . . . . . . . . . . .

69Table 11. Details of Particles Observed in Gastric Aspirates . . . . . . . . . . . . . . . . . . . .

71Table 12. Duration of Fast - Aspiration/Regurgitation . . . . . . . . . . . . . . . . . . . . . .

73Table 13. Duration of Fast - Secondary Outcome Measures . . . . . . . . . . . . . . . . . . . .

74Table 14. Shortened Fluid Fast versus Standard Fast - Thirst . . . . . . . . . . . . . . . . . . . .

75Table 15. Shortened Fluid Fast versus Standard Fast - Hunger . . . . . . . . . . . . . . . . . . .

76Table 16. Shortened Fluid Fast versus Standard Fast - Behaviour . . . . . . . . . . . . . . . . . . .

76Table 17. Shortened Fluid Fast versus Standard Fast - Comfort . . . . . . . . . . . . . . . . . . .

77Table 18. Shortened Fluid Fast versus Standard Fast - Vomiting . . . . . . . . . . . . . . . . . . .

77Table 19. Shortened Solid + Fluid Fast versus Short Fluid Fast - Hunger . . . . . . . . . . . . . . . .

78Table 20. Short Fluid Fast 1 versus Short Fluid Fast 2 - Hunger . . . . . . . . . . . . . . . . . . .

78Table 21. Short Fluid Fast 1 versus Short Fluid Fast 2 - Behaviour . . . . . . . . . . . . . . . . . .

78Table 22. Short Fluid Fast 1 versus Short Fluid Fast 2 - Vomiting . . . . . . . . . . . . . . . . . .

78Table 23. Type of Intake - Aspiration/Regurgitation . . . . . . . . . . . . . . . . . . . . . . .

80Table 24. Type of Intake - Secondary Outcome Measures . . . . . . . . . . . . . . . . . . . . .

81Table 25. Type of Fluid versus Standard Fast - Thirst . . . . . . . . . . . . . . . . . . . . . .

82Table 26. Type of Fluid versus Standard Fast - Hunger . . . . . . . . . . . . . . . . . . . . . .

82Table 27. Type of Fluid versus Standard Fast - Behaviour . . . . . . . . . . . . . . . . . . . . .

83Table 28. Type of Fluid versus Standard Fast - Comfort . . . . . . . . . . . . . . . . . . . . . .

83Table 29. Type of Fluid versus Standard Fast - Vomiting . . . . . . . . . . . . . . . . . . . . .

84Table 30. Volume of Intake - Aspiration/Regurgitation . . . . . . . . . . . . . . . . . . . . . .

iPreoperative fasting for preventing perioperative complications in children (Review)


86Table 31. Volume of Intake - Secondary Outcome Measures . . . . . . . . . . . . . . . . . . . .

87Table 32. Volume of Fluid versus Standard Fast - Thirst . . . . . . . . . . . . . . . . . . . . .

87Table 33. Volume of Fluid versus Standard Fast - Hunger . . . . . . . . . . . . . . . . . . . . .

88Table 34. Volume of Fluid versus Standard Fast - Behaviour . . . . . . . . . . . . . . . . . . . .

89Table 35. Volume of Fluid versus Standard Fast - Comfort . . . . . . . . . . . . . . . . . . . . .

89Table 36. Volume of Fluid versus Standard Fast - Vomiting . . . . . . . . . . . . . . . . . . . .

90Table 37. Volume 1 [V1] versus Volume 2 [V2] - Thirst . . . . . . . . . . . . . . . . . . . . .

90Table 38. Volume 1 [V1] versus Volume 2 [V2] - Hunger . . . . . . . . . . . . . . . . . . . . .

91Table 39. Volume 1 [V1] versus Volume 2 [V2] - Behaviour . . . . . . . . . . . . . . . . . . . .

91Table 40. Sensitivitiy Analysis - excluding trials with inadequate randomisation . . . . . . . . . . . . .

91GRAPHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

91Comparison 01. Duration - Short Fluid Fast versus Standard Fast . . . . . . . . . . . . . . . . . .

92Comparison 02. Duration - Short Solid + Fluid Fast versus Standard Fast . . . . . . . . . . . . . . .

92Comparison 03. Duration - Short Solid + Fluid Fast versus Short Fluid Fast . . . . . . . . . . . . . .

92Comparison 04. Duration - Short Fluid Fast 1 versus Short Fluid Fast 2 . . . . . . . . . . . . . . . .

92Comparison 05. Type of Intake - Fluid versus Standard Fast . . . . . . . . . . . . . . . . . . . .

92Comparison 06. Type of Intake - Fluid 1 versus Fluid 2 . . . . . . . . . . . . . . . . . . . . .

92Comparison 07. Volume of Intake - Volume of Fluid versus Standard Fast . . . . . . . . . . . . . . .

93Comparison 08. Volume of Intake - Volume 1 versus Volume 2 . . . . . . . . . . . . . . . . . . .

93INDEX TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

93COVER SHEET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

94GRAPHS AND OTHER TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

94Fig. 1. Comparison 01. Duration - Short Fluid Fast versus Standard Fast. . . . . . . . . . . . . . . .

9402 Gastric contents - Volume (ml/kg) . . . . . . . . . . . . . . . . . . . . . . . . . .


9603 Gastric contents - pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


9704 Gastric contents - Phenol red based volume (ml) . . . . . . . . . . . . . . . . . . . . .

98Fig. 4. Comparison 02. Duration - Short Solid + Fluid Fast versus Standard Fast. . . . . . . . . . . . . .

9802 Gastric Contents - Volume (ml/kg) . . . . . . . . . . . . . . . . . . . . . . . . . .

98Fig. 5. Comparison 02. Duration - Short Solid + Fluid Fast versus Standard Fast. . . . . . . . . . . . . .

9803 Gastric Contents - pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

99Fig. 6. Comparison 03. Duration - Short Solid + Fluid Fast versus Short Fluid Fast. . . . . . . . . . . . .


100Fig. 7. Comparison 03. Duration - Short Solid + Fluid Fast versus Short Fluid Fast. . . . . . . . . . . . .


101Fig. 8. Comparison 04. Duration - Short Fluid Fast 1 versus Short Fluid Fast 2. . . . . . . . . . . . . .


102Fig. 9. Comparison 04. Duration - Short Fluid Fast 1 versus Short Fluid Fast 2. . . . . . . . . . . . . .


103Fig. 10. Comparison 05. Type of Intake - Fluid versus Standard Fast. . . . . . . . . . . . . . . . . .





10704 Gastric contents - Phenol red based volume (ml) . . . . . . . . . . . . . . . . . . . . .

107Fig. 13. Comparison 06. Type of Intake - Fluid 1 versus Fluid 2. . . . . . . . . . . . . . . . . . .


108Fig. 14. Comparison 06. Type of Intake - Fluid 1 versus Fluid 2. . . . . . . . . . . . . . . . . . .


109Fig. 15. Comparison 07. Volume of Intake - Volume of Fluid versus Standard Fast. . . . . . . . . . . . .


110Fig. 16. Comparison 07. Volume of Intake - Volume of Fluid versus Standard Fast. . . . . . . . . . . . .

iiPreoperative fasting for preventing perioperative complications in children (Review)


11003 Gastric contents - pH values . . . . . . . . . . . . . . . . . . . . . . . . . . . .

112Fig. 17. Comparison 08. Volume of Intake - Volume 1 versus Volume 2. . . . . . . . . . . . . . . . .


112Fig. 18. Comparison 08. Volume of Intake - Volume 1 versus Volume 2. . . . . . . . . . . . . . . . .


iiiPreoperative fasting for preventing perioperative complications in children (Review)


Preoperative fasting for preventing perioperativecomplications in children (Review)

Brady M, Kinn S, O’Rourke K, Randhawa N, Stuart P

This record should be cited as:

Brady M, Kinn S, O’Rourke K, Randhawa N, Stuart P. Preoperative fasting for preventing perioperative complications in children. TheCochrane Database of Systematic Reviews 2005, Issue 2. Art. No.: CD005285. DOI: 10.1002/14651858.CD005285.

This version first published online: 20 April 2005 in Issue 2, 2005.

Date of most recent substantive amendment: 10 February 2005

A B S T R A C T

Background

Children, like adults, are required to fast before general anaesthesia with the aim of reducing the volume and acidity of their stomach

contents. It is thought that fasting reduces the risk of regurgitation and aspiration of gastric contents during surgery. Recent developments

have encouraged a shift from the standard ’nil-by-mouth-from-midnight’ fasting policy to more relaxed regimens. Practice has been

slow to change due to questions relating to the duration of a total fast, the type and amount of intake permitted.

Objectives

To systematically assess the effects of different fasting regimens (duration, type and volume of permitted intake) and the impact on

perioperative complications and patient wellbeing (aspiration, regurgitation, related morbidity, thirst, hunger, pain, comfort, behaviour,

nausea and vomiting) in children.

Search strategy

We searched Cochrane Wounds Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, CINAHL,

the National Research Register, relevant conference proceedings and article reference lists and contacted experts.

Selection criteria

Randomised and quasi randomised controlled trials of preoperative fasting regimens for children were identified.

Data collection and analysis

Data extraction and trial quality assessment was conducted independently by two authors. Trial authors were contacted for additional

information including adverse events.

Main results

Forty-three randomised controlled comparisons (from 23 trials) involving 2350 children considered to be at normal risk of regurgitation

or aspiration during anaesthesia. Only one incidence of aspiration and regurgitation was reported.

Children permitted fluids up to 120 minutes preoperatively were not found to experience higher gastric volumes or lower gastric pH

values than those who fasted. The children permitted fluids were also less thirsty and hungry, better behaved and more comfortable

than those who fasted.

Clear fluids preoperatively did not result in a clinically important difference in the children’s gastric volume or pH. Evidence relating

to the preoperative intake of milk was sparse. The volume of fluid permitted during the preoperative period did not appear to impact

on children’s intraoperative gastric volume or pH contents.

Authors’ conclusions

There is no evidence that children who are not permitted oral fluids for more than six hours preoperatively benefit in terms of

intraoperative gastric volume and pH over children permitted unlimited fluids up to two hours preoperatively. Children permitted

fluids have a more comfortable preoperative experience in terms of thirst and hunger. This evidence applies only to children who are

considered to be at normal risk of aspiration/regurgitation during anaesthesia.



S Y N O P S I S

Most children can safely drink clear liquids until two hours before surgery, although more research is needed for some groups of children

General anaesthetic inhibits the protective reflexes that stop the stomach contents reaching the lungs. In order to prevent the inadvertent

inhalation of stomach contents, children are often advised to have nothing to eat or drink from the midnight before surgery. However,

the review of trials found that drinking clear fluids up to a few hours before surgery did not increase the risk of regurgitation during

or after surgery. Indeed there is an added benefit of a more comfortable preoperative experience in terms of thirst and hunger. Some

children are considered more likely to regurgitate under anaesthetic, including those who are obese, diabetic or have stomach disorders.

More research is needed to determine whether these children can also safely drink up to a few hours before surgery.

B A C K G R O U N D

NEEDS OF CHILDREN FASTING PREOPERATIVELY

The amount and type of food and fluid that children need preop-

eratively varies with age. A neonate (a baby less than one month

old) needs to be fed often with milk (breast milk, non-human milk

or formula) to prevent hunger and thirst while the physiological

needs of the adolescent (child 12 to 18 years) are similar to those

of an adult (Aitkenhead 1996). Reflexes that normally protect the

airway and lungs are depressed or may even be absent during gen-

eral anaesthesia (Aitkenhead 1996, Litman 1999). Food or fluid

regurgitated from the stomach and entering the lungs (aspiration)

may lead to aspiration pneumonia (Mendelson 1946) and even

death. The aspiration of breast milk or infant formula in particular

results in severe damage to the lungs (O’Hare 1996). Children are

usually starved of food and fluid before their surgery to reduce the

risk of aspiration during anaesthesia.

CRITICAL GASTRIC CONTENT VALUES

Fasting aims to reduce the volume and acidity of children’s stom-

ach contents. Children and adults however are often fasted (nil-by-

mouth or NPO) from midnight before their surgery which may

result in a fast of 12 hours or more (MacLean 1993; Veall 1995;

While 1992). The incidence and severity of aspiration pneumo-

nia is thought to be dependent on the volume and acidity of the

stomach contents aspirated. No study has looked at the resulting

pneumonia following aspiration of various volumes and pHs of

gastric contents in humans but there are animal model studies as

listed below such as James 1984 and Raidoo 1990. The link be-

tween fasting, the content of children’s stomachs during surgery

and the risk of injury, should the contents be regurgitated and as-

pirated, is not clear. Many researchers have adopted the arbitrarily

defined critical values of acidity (a pH value of less than 2.5) and

volume (below 0.4 ml/kg) based on unpublished rhesus monkey

data (Roberts 1974). It is widely recognised that these measures

are flawed (Schreiner 1998) and recent research suggests that the

acidity of the contents maybe more relevant than volume (James

1984; Raidoo 1990). The evidence in relation to human breast

milk and formula however is equivocal (O’Hare 1996; O’Hare

1999).

Before stomach contents can be regurgitated and aspirated into

the lungs (leading to aspiration pneumonia) there must be a suf-

ficient volume of contents in the stomach. We do not know what

this critical volume is and it may never be possible to accurately

establish the exact values required to pose a threat to child safety.

As outcome measures, volume and pH value of stomach contents

can only be considered surrogate measures of risk while more re-

liable measures are not (and may never be) available. Children

rarely regurgitate and aspirate their stomach contents while anaes-

thetised and so aspiration pneumonia (and related death) is even

rarer (Engelhardt 2001; Kluger 1999; NCEPOD 2003; SASM

2002). Therefore large multicenter trials would be required to

demonstrate a difference in the effectiveness of a fasting regimen

based on such rare but clinically important outcome measures.

FASTING REGIMENS

Despite the uncertainty surrounding the critical values of gastric

contents older children and adults have traditionally followed a

nil-by-mouth (NPO) from midnight instruction before morning

surgery. For afternoon surgery, an early light breakfast is permitted

which in the UK is typically a cup of tea and slice of toast. The

traditional fast for younger children however appears to be less

globally defined. Fasting regimens shorter than NPO from mid-

night were in place at some centres (Hunt 1987). Typically this

more relaxed approach permitted clear fluids up to four hours pre-

operatively for infants (1 to 12 months), six hours for children (1

to 5 years) and eight hours for children older than 5 years. Other

centres continued to apply the nil-by-mouth-from-midnight pol-

icy.

GUIDELINES

The American Academy of Pediatrics (Committee on Drugs) was

the first to publish specific guidelines for children fasting preoper-

atively. They recommended that clear fluids could be taken up to

two hours prior to anaesthesia while milk or solids could be con-

sumed up to four hours preoperatively for neonates, six hours for

infants and eight hours for children. More recent guidelines pub-

lished by the American Society of Anesthesiologists (ASA) recom-

mended a six-hour fast from non-human milk or infant formula

for neonates and infants but a less conservative fast from breast

milk of four hours preoperatively (see Table 01 for details). Several



other national guidelines suggest that their members adhere to the

recommendations of the ASA (AAGBI 2001; NHSQIS 2003) and

guidelines continue to be developed (RCN).

PRACTICE

Despite the publication of guidelines, many hospitals have been

slow to adjust children’s fasts (Engelhardt 2001; Ferrari 1999; Haas

1998). In a recent survey many British and Irish paediatric anaes-

thetists* allowed children to drink clear fluids up to two hours pre-

operatively (guidelines recommendation) but as many as 25% did

not. Instructions relating to other intake, i.e. breast milk, formula,

non-human milk and solids demonstrated even more variation

(Emerson 1998). Similar variations in permitted milk intake have

also been found (Engelhardt 2001) and in some cases anaesthetists

are permitting milk intake closer to surgery time than is currently

supported by the guidelines (Hofer 2001). Milk, although a liquid,

behaves more like a solid within the stomach with curds forming.

Such inconsistencies in practice may reflect a degree of uncertainty

in evaluating the evidence relating to the preoperative intake of

milk. Local policies require the consensus of the whole preopera-

tive care multidisciplinary team (anaesthetists and nurses) as they

strive to achieve a balance between a child’s unnecessary starvation

and their safety, hydration and well being. Thus, some clinicians

may well be reluctant to alter an existing policy (or their own prac-

tice) that they believe ensures patients’ safety (though not perhaps

their comfort). The disparate nature of the evidence in relation to

fasting from milk and other food and fluid intake makes it difficult

for clinicians to independently evaluate the quality and relevance

of the evidence for themselves.

EVALUATING THE EVIDENCE

Researchers have investigated the duration of fasting, the volume

and the type of intake permitted during a restricted fasting pe-

riod using a variety of outcome measures. We have described the

complexities of using the objective (if surrogate) outcome mea-

sures of gastric content volume and pH above. In some cases non-

absorbable marker dyes were used to measure the volume of chil-

dren’s stomach contents. Phenolsulfonphthalein (phenol red) or

bromosulphthalein (BSP) were added to children’s stomach con-

tents (either before or during surgery) and the concentration of

the dyes in the stomach was expressed as a percentage of the orig-

inal dye ingested and thus provided an indication of gastric emp-

tying. In addition, children’s ratings of thirst, hunger and comfort

were also collected using visual analogue scales (VAS). Very young

children however were unable to complete the scale (or other for-

mal measure) and so, in some cases parents described their child’s

thirst, hunger, behaviour and comfort.

Following our systematic review of preoperative fasting for adults

(Brady 2004) we expected some complexity in evaluating the evi-

dence. Pharmacological co-interventions such as H2 receptor an-

tagonists (for example ranitidine) which function to inhibit the

production of gastric acid, antacids which raise gastric pH or anti-

emetic drugs which increase gastrointestinal motility (for exam-

ple metoclopramide, domperidone) were anticipated. We also ex-

pected the evidence to address a wide age range of children with

fasting policy varying according to the child’s age making compar-

isons difficult. In addition, some children are considered to be at

a high risk of regurgitation and aspiration. For example, children

who require emergency surgery or those who are obese may have

delayed rates of gastric emptying and thus require a specific fast to

ensure an empty stomach (Hofer 2001).

Results that are not statistically significant should be interpreted

with caution as they do not necessarily indicate no difference ex-

ists (Alderson 2004). Instead our interpretation should be clini-cally based on how certain we are that any important benefits or

harms have been excluded (Alderson 2004, Altman 2004, Man-

Son-Hing 2002). This judgement should be made on the basis

of predetermined thresholds or limits of equivalence (Man-Son-

Hing 2002). It is difficult to establish precise values especially in

relation to preoperative fasting and many of the issues have been

mentioned above. They include the low incidence (and reporting)

of the primary outcome of aspiration and regurgitation, the sur-

rogate nature of the alternative primary outcomes gastric pH and

volume, the lack of valid critical gastric values and differences be-

tween individual clinicians’ and patients’ interpretation of what is

considered clinically important (for example Smith 2004). Given

these complexities the picture in relation to the optimum preop-

erative fasting regimen for children is a complex one. We set out

to systematically gather and review the available evidence in rela-

tion to preoperative fasting for children and make it available to

clinicians so that they could independently evaluate the evidence.

*Where we have used the title anaesthetist it is inclusive of the

professional title anesthesiologist (as used in North America).

O B J E C T I V E S

Our objective was to systematically identify, appraise and synthe-

sise the evidence of the effects of different preoperative fasting reg-

imens (duration, type and volume of permitted intake) on periop-

erative complications and patient wellbeing (including aspiration,

regurgitation and related morbidity, thirst, hunger, pain, comfort,

behaviour, nausea, vomiting) in children. We examined the evi-

dence to establish:

1. The optimal duration of a preoperative fast from fluids/solids

for children (in terms of minimising perioperative complications)

During a preoperative fasting period that permits some restricted

intake:

2. What is the optimal type of intake permitted

3. What is the optimal volume of permitted intake in terms of

minimising perioperative complications?

Some children are considered to be at a high risk of aspiration and

related complications, for example those who are obese

4. To what extent does the evidence support different fasting reg-

imens for different high-risk patient populations?



C R I T E R I A F O R C O N S I D E R I N G

S T U D I E S F O R T H I S R E V I E W

Types of studies

All randomised controlled trials (RCTS) which evaluated different

fasting regimens in terms of duration or type/volume of intake

prior to general anaesthesia. Less robust methods of allocation

(for example quasi-randomised trials based on surgical lists) were

considered for inclusion.

Types of participants

Children and young people (18 years of age or less) undergoing

general anaesthesia.

Those considered to be at normal risk of regurgitation/aspiration

are those who are described as healthy (ASA I-II) and undergoing

elective surgery (see Table 02). Children considered to be at high

risk of regurgitation/aspiration include those who are:

(a) emergency cases (especially following trauma);

(b) obese;

(c) have gastric disorders or disease.

The results from the trials based on these subgroups have been

presented separately as specified in the protocol (see Objective 4).

Types of intervention

Within the parallel adult review we defined a standard fast as NPO

from midnight before morning surgery with a light breakfast per-

mitted early in the morning before afternoon surgery. However,

as described above many traditional fasting policies for children

recognise the varied in this population. Typically, these more le-

nient traditional NPO fasts are four hours for infants (1 to 12

months), six hours for children (1 to 5 years) and eight hours for

children older than 5 years. A small drink (up to 30 ml) to assist

the intake of oral medication was also permitted during the stan-

dard fasting period. Studies that evaluated the following fasting

regimens were considered for inclusion in the review. The order

they are presented in corresponds to the objectives of the review.

Types of interventions

1. Duration of fast

(a) Shortened Fluid Fast versus Standard Fast

(b) Shortened Solid and Fluid Fast versus Standard Fast

(c) Shortened Solid and Fluid Fast versus Short Fluid Fast

(d) Short Fluid Fast 1 versus Short Fluid Fast 2

2. Type of Permitted Intake (during a restricted fasting period)

(a) Fluid Intake Permitted (e.g. water, coffee, orange juice) versus

Standard Fast.

(b) Fluid 1 versus Fluid 2

3. Volume of Permitted Intake (during a restricted fasting period)

(a) Volume of Fluid Intake versus Standard Fast

(b) Volume of Fluid Intake 1 versus Volume 2

Investigations which also evaluated the administration of a proki-

netic, H2-receptor antagonist or antacid agent but in which the

control group did not receive a similar administration of the drug

were excluded from the review.

Types of outcome measures

Primary outcomes:

• rate of adverse events (aspiration/regurgitation) or those arising

as a result of aspiration including related morbidity (primarily

aspiration pneumonia) or case fatality;

• volume and/or pH of gastric contents (on induction of anaes-

thesia) with the quality of the aspirate (nature of any particles

observed) described narratively;

• concentration of marker dye (for example phenol red) as an

indicator of gastric emptying.

Secondary outcomes:

• thirst;

• hunger;

• pain;

• behaviour;

• comfort;

• nausea; and

• vomiting.

S E A R C H S T R A T E G Y F O R

I D E N T I F I C A T I O N O F S T U D I E S

See: Wounds Group search strategy

We identified relevant studies through the following sources.

Electronic databases

MEDLINE from 1966 to October 2004

CINAHL from 1982 to October 2004

Cochrane Central Register of Controlled Trials (CENTRAL)

Issue 3 2004

National Research Register (UK) as of October 2004

Cochrane Wounds Group Specialised Register September 2004

The Cochrane Wounds Group Specialised Register has been

complied through searching of the major health databases

including MEDLINE, CINAHL and EMBASE and is regularly

updated through searching of the Cochrane Central Register of

Controlled Trials, handsearching of wound care journals and

relevant conference proceedings.

We searched the above databases using the specific search

strategies detailed in Table 03. The search strategies were

constructed using controlled vocabulary (MeSH) and free text

terms following consultation with the Cochrane Wounds Group.

There were no language restrictions on the searches.



Journal handsearch

We did not handsearch any journals.

Conference proceedings

We hand searched the following key conference proceedings to

identify any relevant studies unavailable in print.

American Society of Anaesthesiologists Annual Meeting 1979 to

2004

Anaesthetic Research Society Abstracts 1978 to April 2003

Canadian Anesthetist’s Society Annual Meeting 1983 to 2004

European Society of Anaesthesiologists Annual Congress

Abstracts 1993 to 2003

Scandinavian Society of Anaesthesiologists 1977 to 2003

Society for Obstetric Anaesthesia and Perinatology Annual

Meeting 1998 to 2002

We checked reference lists from relevant articles for further

sources of preoperative fasting studies.

Personal communication

We attempted to contact the main authors from all studies

included in the review to ask if they had been involved in any

further studies or articles or whether they were aware of any

recent or on going studies (published or unpublished) on the

topic of preoperative fasting. They were also asked if they were

aware of any other individuals prominent or active in the field

that the review authors should contact.

M E T H O D S O F T H E R E V I E W

IDENTIFICATION AND SELECTION OF TRIALS

We identified the relevant literature using the search strategies

detailed in Table 03. Procite, a bibliographic database package, was

used to manage the references. lnvestigative trials which addressed

preoperative fasting amongst children (in terms of duration of fast,

type/volume of intake permitted) were identified. References from

an early version of the search (MEDLINE 1966 to Nov 1999;

CINAHL 1982 to 1999) were screened by a second researcher.

We did not identify any additional trials relevant to the review in

this second screening.

Relevant trials were evaluated (based on the full texts) by three

independent authors. They confirmed the inclusion of the study in

the review. In some cases additional information was required from

the author(s) before a final decision could be made. We resolved

any conflicting decisions through discussion.

DATA EXTRACTION

Two authors (MB and PS) carried out data extraction using a

standardised data extraction sheet which detailed the following:

- children’s age, weight, ASA physical status (see Table 02),

inpatient/outpatient;

- participant inclusion/exclusion criteria;

- fast duration;

- premedication;

- intake permitted (amount, type, duration of fast);

- concurrent interventions;

- operation type (elective, emergency, region);

- type of anaesthesia;

- timing of data collection; and

- outcomes.

In addition, we extracted the following information from those

studies that used residual gastric content values as an outcome

measure:

- instrument and method of gastric content collection;

- method of pH measurement.

Where relevant information was unavailable from the text, we

contacted the trial authors and asked them to provide missing

details. Where trials were published more than once, we used

all the available sources of information to retrieve the maximum

amount of information possible. In the event of any inconsistency

we contacted the authors to resolve the issue. Where this was

not possible the most comprehensive trial report was used and all

publications referring to the results of the trials were recorded.

METHODOLOGICAL QUALITY

A system of coding the methodological quality of trials was adapted

from a report by the Centre for Reviews and Dissemination

(CRD Report Number 4) and piloted. Two authors (MB and SK)

independently evaluated quality and we resolved any disagreement

in coding through discussion. Aspects of methodological quality

considered included:

- listing of inclusion and exclusion criteria;

- evidence of an a priori sample size calculation;

- indication of the comparability of groups at baseline ;

- evidence of an intention-to-treat analysis (coded as yes/no);

- details of the method of generating the randomisation sequence

;

- evidence of concealment of allocation;

- evidence of blinding of assessors.

Details of the coding system can be found in CRD Report Number

4. Where relevant information was unavailable from the text, trial

authors were contacted. Details of whether trial quality evaluations

were based on published information or information provided by

authors can be found in Table 05 Details of Quality Evaluation

by Trial.

STATISTICAL ANALYSIS

Some of the outcome variables in this review (for example residual

gastric values of volume and pH) have skewed distributions. Except

for trials with very small sample sizes, treatment comparisons based

on mean and standard deviation (SD) summary data can be safely

assumed as being approximately normally distributed i.e. with the

mean and SD summary data the usual weighted mean difference

approach is robust to skewness. Unfortunately often authors only

report group medians and ranges (for example minimum and



maximum or 25th and 75th percentiles) for skewed data and

do not present means and SDs. While mean and SD summary

statistics were sought it was not always possible to get these from

the available data or directly from the authors. Where this was the

case, pseudo-values were calculated (O’Rourke 2002) so that the

usual weighted mean difference approach could be used. For the

purposes of this review, the term pseudo is used to indicate that

the values for the mean (pseudo-mean) and SD (pseudo-SD) are

not true mean and SD values. These pseudo-values are estimates

of what the true mean and SD values might be and allow for the

uncertainty entailed by not actually observing them directly, only

estimating them indirectly via other summary measures.

One of the authors (KO’R) has developed two approaches to the

calculation of these values (O’Rourke 2002). The first, which is

fairly mathematical, calculates and uses a likelihood based on the

summaries in hand and requires the use of numerical optimization

software (O’Rourke 2002). The second avoids the need for

numerical optimization software by drawing on statistical methods

for dealing with reported group medians and various ranges as

linear combinations of order statistics (Arnold 1992). This method

uses least squares to estimate the best linear estimates of the

unreported mean and SD along with an appropriate standard error

for the pseudo-mean, which again reflects uncertainty entailed by

not actually observing the mean. These pseudo-means and pseudo-

SDs are then entered into RevMan and treated as if they were

actually observed (again, the process above having made allowance

for them being estimated rather than actually observed). In general

the first approach was used and where this was not possible the

second approach was used. Except for highly skewed data, the

results tend to be very similar and for highly skewed data the

first approach is arguably more correct. Sensitivity analysis for the

amount of skew can be carried out for the second approach, and

this was done whenever the first approach was not available. With

the pseudo-means and pseudo-SDs in hand, the usual methods

for meta-analysis of means and SDs via weighted mean differences

can be carried out.

In some cases a trial which randomly allocated children to

two (or more) intervention groups but only one control group

were included within one meta-analysis (e.g. Splinter 1990a and

Splinter 1990b are included in Comparison 05: Type of Intake

- Fluid versus Standard Fast, Outcome: 03 Gastric Contents -

pH 04 Fruit Juice versus Standard Fast). Where this was the

case, we avoided counting the individuals in the control group

twice by ’splitting’ the numbers in the control group across

both interventions (Oxford 2001). This splitting ensures that

the pooled results are correct, but does understate the evidence

available for the various individual comparisons in that these

individual confidence intervals are wider than they ideally need to

be. Division of the number of children was as equal as possible

using whole numbers.

The primary continuous outcome variables in relation to

gastric content (volume, pH, marker dye concentration) were

summarised using weighted mean differences. Chi squared

calculations (significance level set at p < 0.1) were made using

RevMan 4.2.1. Trials which evaluated similar interventions

using similar outcome measures in the absence of clinical or

methodological heterogeneity were pooled. We used a random

effects model in the presence of statistical heterogeneity and to pool

summary data that included pseudo-value calculations. Details of

these aspects will be reported for each section.

Sensitivity analyses were planned based on the method of

randomisation and the presence of assessor blinding. The various

subjective approaches used to evaluate the secondary outcome

measures of thirst, hunger, behaviour, comfort, nausea and

vomiting could not be pooled in a quantitative fashion but were

summarised in a tabular format. Details of the measurement tool,

the timing of the measurement, the comparisons made and the

results of the comparison were profiled and discussed in a narrative

fashion within the results section.

INTERPRETING THE EVIDENCE

To enable us to interpret the evidence from the meta-analyses

where no significant difference between the groups was observed

ideally requires some definition of threshold values or limits of

equivalence. We mentioned above the lack of valid gastric content

volume and pH limits of equivalence. However, some degree of

interpretation is possible. Where the results of a meta-analysis

demonstrated very narrow confidence intervals it was possible to

state that the results provided little indication of an important

clinical difference between the two groups. Similarly, where the

confidence intervals were clearly wide and scattered, a statement

was made to indicate that based on this result, insufficient evidence

was available at present to state whether or not an important

difference exists. In some cases the decision as to whether or not

a clinically important difference existed was more subjective and

in such cases individual readers should interpret the results within

their own framework of clinical importance.

D E S C R I P T I O N O F S T U D I E S

Twenty three trials met the criteria for inclusion and included

children up to 18 years of age. Splinter 1991 had extended the

participant age range to include individuals up to the age of 19

and a decision was made to include this trial within this review of

preoperative fasting for children. Nicolson 1992 included children

described as ASA IV who were all undergoing cardiac surgery. We

included this work within the main body of the results section as

the classification of ASA IV reflects the risk of surgery rather than

a specific increase in the regurgitation/aspiration risk.

The 23 trials were conducted in a number of different coun-

tries. Ten were conducted in Canada (Crawford 1990; Goresky

1992; Sandhar 1989; Splinter 1989; Splinter 1990; Splinter 1991;



Splinter Schaefer 1a; Splinter Schaefer 1b; Splinter Schaefer 2;

Splinter Schaefer 3), five in USA (Cook-Sather 2003; Miller

1990; Nicolson 1992; Schreiner 1990; Welborn 1993), two in

Japan (Kushikata 1996; Maekawa 1993) and one each in China

(Aun 1990), India (Gombar 1997), UK (Meakin 1985), Mexico

(Moyao-García 2001) Italy (Sarti 1991) and Australia (van der

Walt 1986). Given the wide range of geographical settings there

is remarkable methodological consistency across all 23 trials that

sampled gastric contents.

Gastric contents were generally collected using a syringe to aspirate

the stomach contents following insertion of a tube. Two trials used

a nasogastric tube (Aun 1990; Gombar 1997) while Moyao-García

2001 mention the collection of gastric contents during an endo-

scopic examination. The remaining 20 trials all used oro-gastric

tubing which was in some cases further described as multi orifice

(Cook Sather 2003; Crawford 1990; Sandhar 1989; Sarti 1991),

Salem sump (Goresky 1992; Kushikata 1996; Maekawa 1993;

Nicolson 1992; Schreiner 1990; Splinter 1989; Splinter 1990;

Splinter Schaefer 3; Splinter Schaefer 2), Ryles (Meakin 1985),

Levine (Spinter Schaefer 1a; Spinter Schaefer 1b) or a catheter

(Welborn 1993). Sizes of tubing ranged from 10 to 18 gauge and

all but seven trials (Cook-Sather 2003; Goresky 1992; Kushikata

1996; Meakin 1985; Miller 1990, Moyao-García 2001; Sandhar

1989) described tilting the children to ensure the maximum vol-

ume of gastric contents could be aspirated. In all cases the collec-

tion of gastric contents appears to have taken place within a similar

time frame just following induction and intubation. Nine of these

trials also described the quality of the aspirated gastric contents

in terms of any particles observed (Cook-Sather 2003; Kushikata

1996; Maekawa 1993; Meakin 1985; Moyao-García 2001; Splin-

ter 1990; Splinter 1991; Splinter Schaefer 2; Splinter Schaefer 3).

All but one trial (Gombar 1997) that collected gastric volume

as an outcome measure also measured gastric pH. A variety of

tools were used to measure pH values including pH radiometer

(Crawford 1990; Sarti 1991), pH meter (Goresky 1992; Maekawa

1993; Welborn 1993), electrode (Meakin 1985), digital Ionalyzer

pH meter (Nicolson 1992; Sandhar 1989; Scheriner 1990 ), and

pH paper (Aun 1990; Miller 1990; Moyao-García 2001; Splinter

1989; Splinter 1990; Splinter 1991; Splinter Schaefer 1a; Splinter

Schaefer 1b; Splinter Schaefer 2; Splinter Schaefer 3; van der Walt

1986). Some reports also described calibration of the pH mea-

surement tool (Crawford 1990; Goresky 1992; Nicolson 1992;

Sandhar 1989; Schreiner 1990; Welborn 1993). It is unclear how

Cook-Sather 2003 and Kushikata 1996 measured pH.

Eleven trials reported at least one of the secondary outcomes

addressed by this review; thirst (Gombar 1997; Nicolson 1992;

Splinter 1989; Splinter 1990; Splinter 1991), hunger (Cook-

Sather 2003; Kushikata 1996; Nicolson 1992; Splinter 1989;

Splinter 1990; Splinter 1991), behaviour (Cook-Sather 2003;

Gombar 1997; Schreiner 1990; Splinter 1990), comfort (Nicol-

son 1992; Schreiner 1990) and vomiting (Aun 1990; Cook-Sather

2003; Goresky 1992; Maekawa 1993; Schreiner 1990). No trial

reported children’s experience of nausea during the preoperative

period. Given the wide variety of methods used to evaluate these

secondary measures and the subjective nature of their report (in

most cases children’s self-report) a qualitative approach to between-

trial comparisons was adopted. Details of the secondary outcome

measures employed (detailing the method and timing of the data

collection) will be presented within the results section. Splinter

1989; Splinter 1990 and Splinter 1991 employed a linear analogue

scale to measure secondary outcomes, which will be referred to

here as a visual analogue scale.

No trial specifically recruited children considered to be at a high

risk of regurgitation/aspiration during anaesthesia, for example

obese children (calculated with reference to age, height, weight).

All the remaining trials recruited children undergoing elective

surgery with most described as ASA I-II (Table 02). Five trials

did not report the children’s ASA status (Kushikata 1996; Splinter

Schaefer 1a; Splinter Schaefer 1b; van der Walt 1986; Welborn

1993) but described the children as ’healthy’. One trial (Nicolson

1992), was based on children undergoing elective cardiac surgery

classed as ASA II-IV. Most trials took measures to exclude gastric

disease, disorders and/or drugs that affected gastric secretion or

motility with only three failing to indicate these as exclusion cri-

teria (Kushikata 1996; Sarti 1991; Welborn 1993).

In conducting this systematic review we had prespecified three

main age groups of children that we felt were of clinical relevance

- neonate (under 1 month), infant (1 to 12 months), and children

(over 12 months). While eighteen trials had limited recruitment

to children other trials had recruited across age ranges (see Table

04 for details). Three had recruited neonates (Cook Sather 2003;

Splinter Schaefer 3; van der Walt 1986), five had recruited infants

(Cook Sather 2003; Miller 1990; Nicolson 1992; Splinter Schaefer

3; van der Walt 1986) and five had recruited older children (over

12 years) that could be classified as adolescents (Crawford 1990;

Maekawa 1993; Meakin 1985; Sandhar 1989; Schreiner 1990;

Splinter 1991). There was a considerable degree of overlap within

and between trials and it was not always possible to extract the age-

group specific data. Given the degree of overlap all age group data

will initially be presented together which will then be followed

with a further exploration of age specific issues as permitted by the

available data.

M E T H O D O L O G I C A L Q U A L I T Y

This review describes the randomised allocation of 2350 children

across 59 control/intervention arms in 23 trials. Twenty-five chil-

dren in Gombar 1997 were not included in the review as the inter-

vention they were exposed to did not contribute to the evaluation

of a preoperative fasting regimen but evaluated the effectiveness of

a pharmacological intervention. The trials within the review were

small with all control and intervention groups consisting of fewer



than 100 children. Only three trials randomised more than 150

children; Goresky 1992 (n = 240); Splinter 1991 (n = 152); Wel-

born 1993 (n = 200). Nine trials randomised between 100 and 150

children (Crawford 1990; Maekawa 1993; Meakin 1985; Nicol-

son 1992; Schreiner 1990; Splinter Schaefer 1b; Splinter Schae-

fer 2; Splinter Schaefer 3; van der Walt 1986) and the remaining

eleven trials were based on fewer than 100 children (Aun 1990;

Cook-Sather 2003; Gombar 1997; Kushikata 1996; Miller 1990;

Moyao-García 2001; Sandhar 1989; Sarti 1991; Splinter 1989;

Splinter 1990; Splinter Schaefer 1a).

The quality of the investigative studies was independently exam-

ined by two of the authors (MB and SK). The method of gen-

erating the randomisation sequence was evaluated as adequate in

16 trials (Aun 1990; Cook-Sather 2003; Crawford 1990; Gombar

1997; Miller 1990; Moyao-García 2001; Sandhar 1989; Schreiner

1990; Splinter 1989; Splinter 1990; Splinter 1991; Splinter Schae-

fer 1a; Splinter Schaefer 1b; Splinter Schaefer 2; Spinter Schaefer

3; van der Walt 1986), inadequate in three trials (Kushikata 1996;

Meakin 1985; Welborn 1993) and unclear for the remaining four

trials (Goresky 1992; Maekawa 1993; Nicolson 1992; Sarti 1991).

Similarly methods of concealment of allocation varied. Conceal-

ment of allocation was classified as adequate in five trials (Aun

1990; Cook-Sather 2003; Moyao-García 2001; Nicolson 1992;

Schreiner 1990), inadequate in three (Kushikata 1996; Meakin

1985; Welborn 1993), and unclear in the remaining fifteen trials

(Crawford 1990; Gombar 1997; Goresky 1992; Maekawa 1993;

Miller 1990; Sandhar 1989; Sarti 1991; Splinter 1989; Splinter

1990; Splinter 1991; Splinter Schaefer 1a; Splinter Schaefer 1b;

Splinter Schaefer 2; Spinter Schaefer 3; van der Walt 1986) (see

Characteristics of Included Studies and Table 05).

Blinding of participants and assessors as to the intake of food/fluid

is difficult if not impossible to achieve in a trial evaluating a pre-

operative fasting regimen. However, blinding of the anaesthetist,

sample collector and assessor is possible for trials that aim to mea-

sure children’s gastric content values. Children cannot be blinded

as to whether or not they have had something to eat or drink, and

even blinding as to the volume of intake is difficult. Some compar-

isons do allow for such blinding. Two trials blinded children as to

the type of pharmacological co intervention by administering ei-

ther placebo or ranitidine (Goresky 1992; Sandhar 1989) but eval-

uation of such pharmacological interventions was not the focus of

this review. The difficulty of blinding children (and their parents)

as to whether they have had a drink or eaten is acknowledged and

the impact this might have on the collection of outcome measures

(e.g. ratings of thirst, hunger, comfort) is recognised and will be

returned to in the results and discussion sections.

For the purposes of evaluating the quality of the trials, blinding

ratings refer to the adequacy of blinding the assessors that collected

and measured the gastric content values only and not to the blind-

ing of participants or individuals involved in the collection of pa-

tient reported secondary outcome measures. Blinding details were

unavailable for five trials (Kushikata 1996; Miller 1990; Sandhar

1989; Sarti 1991; Welborn 1993) while for an additional three

trials there were some qualifications to the blinding observed. In

these three cases the blinding was restricted to either the raniti-

dine/placebo intervention (Goresky 1992), the assessor collecting

the thirst and behaviour reports (Gombar 1997), or the assessor

measuring gastric pH and food particles (Meakin 1989). The re-

maining 15 trials were found to have adequate blinding of the

assessors collecting gastric pH and volume measures.

Inclusion and exclusion criteria were available for most trials, al-

though the degree of reporting detail varied (see Characteristics

of Included Studies table). The exclusion criteria for three trials

were unavailable (Kushikata 1996; Welborn 1993; Sarti 1991).

We noted five trials described an a priori sample size calculation

(Cook-Sather 2003; Splinter 1990; Splinter Schaefer 1a; Splinter

Schaefer 1b; Splinter Schaefer 2) although one trial recalculated

this during the trial (Cook-Sather 2003). The remaining trials

made no reference to such a calculation.

Participant groups were demonstrated to be comparable at base-

line by most trials although the level of comparison varied. Three

trials found significant differences between the groups. Gombar

found the children who were fasted in the standard manner were

heavier, older and had more females than the intervention group

while the children given 10 ml/kg of fluid were lighter than the

children given 6ml/kg in the trial by Splinter 1990. Neither trial-

ists undertook an adjusted analysis to account for these differences.

The children permitted intake in the van der Walt 1986 study we

heavier than those that continued to fast. The comparability of

groups in Crawford 1990 was unclear from the text.

Intention to treat analysis was considered by Cook-Sather 2003

but following protocol deviations (n = 30) they only reported a

per protocol analysis. Twelve trials reported omission of some data

from analysis (see Characteristics of Included Studies) and these

usually referred to an absence of pH values as no aspirate was

available from the participant. The remaining 10 trials did not

report any withdrawals and in all trials except one it was clear that

all participants had been included in the data analysis (Moyao-

García 2001; Sarti 1991; Splinter 1989; Splinter 1990; Splinter

1991; Spinter Schaefer 1a; Spinter Schaefer 1b; Spinter Schaefer

2; Spinter Schaefer 3). Quality was not used to weight the trials

in the meta-analyses of this review but will be commented on, as

appropriate, within the results and discussion sections. Full details

of the trials’ quality evaluation are presented in Table 05 Details

of Quality Evaluation by Trials.

As observed in the systematic review relating to adults fasting

preoperatively (Brady 2004), it became clear from examining the

available mean and standard deviation (SD) summary data in this

review that there was also some indication of skewed distribution

(mean/SD < 1.64). Given the nature of the gastric volume and

pH continuous outcome measures, it was not unexpected to find

naturally positively skewed distributions. As described previously



(Brady 2004), some authors had as a result chosen to present the

skewed distributions using median and range values. In our pre-

vious work we developed a method of calculating pseudo-values

(described above) which allowed us to include within the meta-

analysis those trials that reported only median and range summary

statistics.

All 23 trials measured children’s intra-operative gastric contents

volume and pH. Methods of reporting the summary data for these

continuous outcome measures (volume and pH) varied across tri-

als. Mean and standard deviation gastric content values (volume

and pH) were available in either published or unpublished format

for 16 trials (details in Tables 06 to 09). Meakin 1985 reported the

mean and standard deviation values for the gastric volume mea-

sure only. Mean and range values were reported for both volume

and pH measures (Sandhar 1989; Welborn 1993) or for volume

alone (Aun 1990) while Meakin 1985 reported gastric pH using

median and range values and van der Walt 1986 only reported

range values for both gastric volume and pH. Four trials required

pseudo-values calculated for gastric volume summary data (Aun

1990; Sandhar 1989; van der Walt 1986; Welborn 1993) and for

pH summary data (Meakin 1985; Sandhar 1989; van der Walt

1986; Welborn 1993). Details of the summary statistics reported

by the authors and (when relevant) pseudo-values used within the

meta-analysis can be referred to in Table 06 - Table 09.

R E S U L T S

We addressed four main elements of a preoperative fast within this

review, namely:

(A) the duration of fast;

(B) the type of permitted intake;

(C) the volume of intake permitted during a fasting period and

(D) patient risk of aspiration/regurgitation during anaesthesia as

perceived by the peri-operative team.

The evidence in relation to these four elements of preoperative fast-

ing was evaluated within this review with reference to the primary

outcome measures of aspiration/regurgitation, and gastric content

values (volume, pH, marker dye concentration). The evidence re-

garding the secondary outcome measures of thirst, hunger, pain,

nausea, vomiting and anxiety was also considered and details are

presented in Table 13 - Table 39 with reference made within the

text to the relevant tables as appropriate. For a key to these tables

refer to Table 10.

There is a substantial body of evidence in relation to preoperative

fasting for children and the evidence presented within this review

is extensive. The presentation of the results is organised by the

four parameters of a preoperative fast (as listed above) and within

each of the parameters by outcome measure, which includes (01)

adverse events (02) gastric volume, (03) gastric pH (04) marker

dye and (05) secondary outcomes (as listed above). Whenever pos-

sible labels for each section correspond with the relevant meta-

analysis graph. The incidence of aspiration/regurgitation (and any

associated morbidity/mortality), one of the primary outcomes of

this review, was not consistently addressed by the included trials.

Whenever possible these details were directly sought from the au-

thors. Available results have been presented in Tables 12, 23 and

30.

Eight of the 23 trials included made comparisons between three

or more randomly allocated participant groups of relevance to this

review (Crawford 1990; Goresky 1992; Maekawa 1993; Meakin

1985; Sandhar 1989; Splinter 1990; Splinter Schafer 3; van der

Walt 1986). Thus, for these trials above, two or more comparisons

were made within each trial. For the purposes of this review a

distinction was made between these comparisons by using the

suffix a, b, c etc to the trial name as appropriate (e.g. Splinter

1990a; Splinter 1990b). Details of the randomised comparisons

are available in the Characteristics of Included Studies Table and

to reduce the complexity of the language used within the text, they

will be referred to as trials throughout the remainder of the review.

Following the adult preoperative fasting review (Brady 2004) there

was a clear indication that comparisons that included a H2 re-

ceptor antagonist co-intervention should be presented separately.

We adopted this approach a priori for this review and any meta-

analysis that is based on comparisons that included a H2 receptor

antagonist co-intervention are clearly marked as ’+ H2 receptor

antagonist’.

Given the complexity of the topic and the number of comparisons

and outcomes addressed within this review, readers can refer to an

overview of the results available at the end of the results section.

A. Duration of Fast

Trials that compared two different fasting regimens on the basis of

the duration of the preoperative nil-by-mouth fast are presented in

this section. Standard fasting regimens were compared to a short

fluid fast and a short solid fast, while shortened fluid fasts were

compared to a short solid fast or other short fluid fasts. Chil-

dren within these trials were all considered to be at normal risk

of regurgitation/aspiration during anaesthesia, undergoing elec-

tive surgery and generally ASA I-II. The evidence in relation to

each comparison is presented by outcome used to measure the ef-

fectiveness of the fasting regimens; (01) aspiration/regurgitation,

(02) the volume of gastric contents, (03) the pH of gastric con-

tents, (04) measures of gastric volume and emptying using marker

dye and the secondary outcomes. An overview is available at the

end of the results section.

Comparison 01: Duration - short fluid fast versus standard fast

Outcome 01: Aspiration/RegurgitationEleven trials reported the incidence of adverse events including

regurgitation and aspiration, though an additional eight authors

provided unpublished data on this outcome. Of the 19 trials that

specifically commented on the occurrence of aspiration/regurgita-

tion, only Goresky 1992a and Goresky 1992b reported any events



of note. Only one incidence of aspiration/regurgitation was ob-

served and occurred within the group that were permitted flu-

ids up to 120 minutes preoperatively. The authors felt this inci-

dence was related to airway management rather than as a result

of the study intervention (Goresky 1992a). The additional eight

events reported included a possible vaso-vagal response (flushing

and sweating post intervention) and children that vomited or spat

out the intervention fluid. These latter events occurred across the

two trials Goresky 1992a and Goresky 1992b but it is unclear to

which groups the children belonged. Details can be found in Table

12 Duration of Fast - Aspiration/Regurgitation.

Outcome 02: Gastric Contents - VolumeTwenty-four trials measured intra-operative gastric volume for a

standard preoperative fast versus a fast that permitted some fluid

intake. The trials within this section are grouped based on the tim-

ing of the experimental intake; fluids permitted up to 120 min-

utes, 150 minutes, 180 minutes and 240 minutes preoperatively.

The results were pooled within the meta-analysis using a random

effects model and can be referred to in Comparison: 01 Duration

- Shortened Fluid Fast versus Standard Fast; Outcome 02 Gastric

Contents - Volume (ml/kg).

(i) Fluids (up to 120 minutes preoperatively) versus Standard Fast

Eight trials compared the intake of fluids up to 120 minutes pre-

operatively (n = 248) with a standard fasting regimen (n = 261).

Pseudo-values were required for two trials (Sandhar 1989a; Wel-

born 1993). Goresky 1992a also compared the intake of fluids up

to 120 minutes preoperatively with a group that followed a tra-

ditional fast. The gastric volume data were reported as one cross-

group summary mean (0.42ml/kg) and standard deviation value

(0.04). As a result these data could not be included within this (or

any other relevant) meta-analysis. On pooling the available data

there was no evidence of a difference for gastric volume (weighted

mean difference (WMD) 0.03 ml/kg confidence interval (CI) 95%

-0.03 to 0.10).

(ii) Fluids (up to 120 minutes preoperatively) versus Standard Fast

(+ H2 Receptor Antagonist)

Two trials that compared the intake of fluid up to 120 minutes

preoperatively (n = 18) to a standard fasting regimen (n = 15)

also administered ranitidine, a H2 receptor antagonist, to all the

children (Goresky 1992b; Sandhar 1989b). Psuedo-standard de-

viation values were calculated for the Sandhar 1989b trial to allow

inclusion of the trial within the meta-analysis. There was no ev-

idence of a difference between the intra-operative gastric volume

of these groups that fasted and those that were permitted fluids

(WMD 0.01ml/kg 95% CI -0.12 to 0.14). Separate summary data

for the groups in the Goresky 1992b trial were not available and

so the data could not be pooled.

(iii) Fluids (up to 150 minutes preoperatively) versus Standard

Fast

The intra-operative gastric volume of 102 children permitted flu-

ids up to 150 minutes preoperatively was compared to the gastric

volume of 71 children that followed a standard fast across three

trials (Splinter 1989; Splinter 1990a; Splinter 1990b). There was

no evidence of a difference between the groups’ gastric content

volume (WMD 0.07 ml/kg 95% CI -0.25 to 0.39).

(iv) Fluids (up to 180 minutes preoperatively) versus Standard Fast

Eight trials asked children to take fluids up to 180 minutes pre-

operatively while a second group of children continued to fast in

the standard manner (Gombar 1997; Miller 1990; Moyao-García

2001; Splinter 1991; Splinter Schaefer 2; van der Walt 1986a; van

der Walt 1986b; van der Walt 1986c). Three of the comparisons

did not provide mean and standard deviation summary data and

so pseudo-values were calculated to permit inclusion of these tri-

als within the meta-analysis (van der Walt 1986a; van der Walt

1986b; van der Walt 1986c). On pooling the data the children

permitted fluids up to 180 minutes prior to surgery (n = 287) had

a significantly lower volume of gastric contents than those children

that fasted in the standard manner (n = 243) (WMD -0.12 ml/kg

95% CI -0.22 to -0.03) p = 0.01.

(v) Fluids (up to 240 minutes preoperatively) versus Standard Fast

Sixty children were randomised to drink fluids up to 240 minutes

preoperatively while 65 others followed a traditional fasting policy

across three trials (Aun 1990; Maekawa 1993b; Meakin 1985e).

Pseudo-standard deviation values were calculated for Aun 1990.

On pooling the data there was no evidence of a difference between

the two groups (WMD 0.03ml/kg 95% CI -0.10 to 0.17).

Outcome 03: Gastric Contents - pHTwenty-three trials compared the intra-operative gastric pH of

children after a shortened fluid fast compared with a standard fast.

This represents all but one of the trials (Aun 1990) that measured

gastric content volume (as detailed above). In many trials individ-

ual children’s gastric pH could not be measured as a gastric sam-

ple could not always be collected and so the numbers of children

included in this comparison differs from the numbers of children

observed in the gastric volume comparison above. A total of 695

children were permitted a shorter fluid fast while 632 continued

a standard preoperative fast. The results of this comparison are

presented in Comparison: 01 Duration - Short Fluid Fast versus

Standard Fast; Outcome 03 Gastric Contents - pH. As with the

gastric volume outcome measure presented above, the trials are

grouped based on the timing of intake (up to 120 minutes, 150

minutes, 180 minutes and 240 minutes preoperatively). The trial

results were pooled using a random effects model.


Eight trials compared the intake of fluids up to 120 minutes

preoperatively (n = 246) and a standard fasting regimen (n =

238) (Goresky 1992a; Maekawa 1993a; Meakin 1985a; Nicol-

son 1992; Sandhar 1989a; Sarti 1991; Schreiner 1990; Welborn

1993). Psuedo-values were calculated for three of the trials (Meakin

1985a; Sandhar 1989a; Welborn 1993). On pooling the data there

was no evidence of a difference in gastric pH (WMD 0.04, 95%



CI -0.01 to 0.09) and the narrow confidence intervals indicate that

an important difference between the groups is highly unlikely.


(+ H2 Receptor Antagonist)

Two additional trials permitted some children fluids up to 120

minutes preoperatively (n = 68) and compared their gastric pH

with that of children that continued a standard fasting regimen (n =

61) (Sandhar 1989b; Goresky 1992b). The children in these trials

were all also administered ranitidine (an H2 receptor antagonist).

Pseudo-values were calculated for the Sandhar 1989b trial and on

pooling the data there was no statistically significant difference

in gastric pH (WMD 0.53, 95% CI -0.20 to 1.26) though this

comparison is underpowered with only 129 children.


Fast

Children permitted fluids up to 150 minutes preoperatively (n =

102) were compared with those who remained fasting (n = 71) in

three trials (Splinter 1989; Splinter 1990a; Splinter 1990b). On

pooling the data there was no evidence of a difference in gastric pH

values between the groups (WMD 0.19, 95% CI -0.11 to 0.49).

(iv) Fluids (up to 180 minutes preoperatively) versus Standard Fast

Eight trials compared fluid intake up to 180 minutes preopera-

tively (n = 242) to a standard fast (n = 223) by evaluating children’s

intra-operative gastric pH (Gombar 1997; Miller 1990; Moyao-

García 2001; Splinter 1991; Splinter Schaefer 2; van der Walt

1986a; van der Walt 1986b; van der Walt 1986c). Pseudo-values

were required for three trials (van der Walt 1986a; van der Walt

1986b; van der Walt 1986c). After pooling the data, there was

no evidence of a difference in gastric pH (WMD 0.32, 95% CI

-0.14 to 0.78) though the high degree of heterogeneity (I2= 88%)

should be noted.

(v) Fluids (up to 240 minutes preoperatively) versus Standard Fast

Both Meakin 1985e and Maekawa 1993b permitted children flu-

ids up to 240 minutes preoperatively (n = 37) while a second group

continued to fast (n = 39). Although Aun 1990 also compared the

intake of fluids up to 240 minutes preoperatively to a standard fast

they did not report separate gastric content pH summary data for

the two groups. Instead, they reported that all children in the study

had a gastric pH of < 2.5. Pseudo-standard deviation values were

required for Meakin 1985e and on pooling these results with those

from Maekawa 1993b, there was no indication of a difference in

intra-operative gastric pH (WMD -0.02, 95% CI -0.23 to 0.18).

Whilst this comparison involved only 76 children the confidence

intervals are narrow and there is no evidence of heterogeneity.

Outcome 04: Gastric Contents - Marker DyesPhenol red

Three trials used phenolsulfonphthalein (also known as PSP or

phenol red) as a marker dye to measure gastric volume.


Sandhar 1989a used the marker dye to compare gastric volume

after the intake of fluids up to 120 minutes preoperatively (n =

13) and with a standard fast (n = 19). One child who fasted for

an hour after the intervention was found to have a 33% percent

of dye retrieval. Dye retrieval for the remaining children was less

than five percent and for many children no dye was found. No

additional details were available.


(+ H2 receptor antagonist)

A second study compared the intake of fluids up to 120 minutes

preoperatively (n = 15) with the standard fast (n = 18) but included

a ranitidine co-intervention (Sandhar 1989b). Dye retrieval was

12% for one child that fasted for one hour following a juice and

ranitidine intervention while the remaining children had a dye

retrieval of less than five percent.


Fast

Miller 1990 used phenol red to calculate the volume of intra-op-

erative gastric contents (expressed in ml). The marker dye based

measure of gastric volume of the children permitted fluids up to

180 minutes preoperatively (n = 19) and those that followed a

standard fast (n = 25) are presented in Comparison: 01 Duration -

Short Fluid Fast versus Standard Fast; Outcome: 04 Gastric Con-

tents - Phenol Red. There was no evidence of a between group

difference in gastric volume (WMD -3.10 ml, 95% CI -6.66 to

0.46) though with an increased sample size this result may have

achieved statistical significance.

Bromosulphthalein

Two trials used the marker dye bromosulphthalein (also known as

sulfobromophthalein or BSP).


Two trials used the dye bromosulphthalein to measure the con-

tribution of the ingested fluids to the intra-operative gastric vol-

ume (Goresky 1992a; Goresky 1992b). Results were reported as a

percentage (%) of recovered dye. Both trials compared the intake

of fluids up to 120 minutes preoperatively to the standard fasting

regimen but one included a ranitidine (H2 receptor antagonist)

co-intervention. In reporting the results the two standard fasting

groups were combined and compared to the recovered marker dye

values from the combined group permitted fluids. The fluid in-

take was reported to have had an insignificant effect on the dye

recovery and the dye recovery represented less than 0.3% of the

volume of intake at the time of marker dye administration. More

dye was recovered from those children given ranitidine than the

children that did not receive this co-intervention (p < 0.001). No

other details were available.

Secondary OutcomesTwelve of the total 24 comparisons presented within this review

compared a shortened fluid fast to a standard fast by evaluating

children’s thirst, hunger, behaviour, comfort and vomiting. No

trial addressed nausea. Additional information on the methods of



measurement and the nature of the comparisons made is presented

in Table 13 Duration of Fast - Secondary Outcome Measures. The

key to this table is available in Table 10.

• Thirst

Six trials comparing a shortened fluid fast to a standard preopera-

tive fasting regimen considered children’s thirst. In all cases visual

analogue scales were completed immediately preoperatively (time

point f or g) (see Table 10 for key). The children (Splinter 1989;

Splinter 1990a; Splinter 1990b; Gombar 1997; Splinter 1991) or

their parents (Splinter 1989; Nicolson 1992) were asked to de-

scribe their perceptions of thirst by completing the VAS scale. De-

tails of the tools used and the timing of measures are presented

in Table 14 - Shortened Fluid Fast versus Standard Fast - Thirst.

Where differences were noted, the children (or the parents of chil-

dren) who took fluids up to 150 minutes and 180 minutes preop-

eratively described less preoperative thirst than those that followed

a standard fasting regimen. One trial reported no difference in

reported thirst between the children given apple juice 150 min-

utes preoperatively and those that continued fasting preoperatively

(Splinter 1990b).

• Hunger

Five trials compared a shortened fluid fasting regimen with a stan-

dard fasting regimen by measuring patients’ hunger. A visual ana-

logue scale was used to rate preoperative hunger by either a par-

ent (Nicolson 1992; Splinter 1989) or by the children themselves

(Splinter 1989; Splinter 1990a; Splinter 1990b; Splinter 1991).

Details can be referred to in Table 15 Shortened Fluid Fast versus

Standard Fast - Hunger. In three trials there was no difference be-

tween the children’s report of hunger regardless of whether they

had fasted in the traditional manner or received fluids up to 150

(Splinter 1990a; Splinter 1990b) or 180 minutes preoperatively

(Splinter 1991). In the remaining trials, children (and/or parents

of children) given fluids up to 120 (Nicolson 1992) or 150 min-

utes preoperatively (Splinter 1989) reported less hunger.

• Behaviour

The preoperative behaviour of children was evaluated by parents

using a VAS in four trials. Parents were asked to rate how irri-

table (Schreiner 1990; Gombar 1997) or irritable/upset (Splin-

ter 1990a; Splinter 1990b) their child was. Schreiner 1990 and

Splinter 1990a found the children permitted fluids 120 minutes

preoperatively were rated as statistically significantly less irritable

than those who fasted. Interestingly, Splinter 1990a (fluids up to

120 minutes) and Gombar 1997 (fluids up to 180 minutes) found

no difference. Details are presented in Table 16 Shortened Fluid

Fast versus Standard Fast - Behaviour.

• Comfort

Parents in two trials used a VAS to describe their child’s com-

fort during (Nicolson 1992) or tolerance of (Schreiner 1990) the

preoperative experience. Both trials found the children permitted

fluids up to 120 minutes preoperatively were described as statis-

tically significantly more comfortable (or as tolerating the pre-

operative experience better) than the children who fasted in the

standard way. See Table 17 Shortened Fluid Fast versus Standard

Fast - Comfort. Schreiner 1990 also asked parents of children who

had a prior experience of surgery and who were randomised to

receive fluids preoperatively in their trial to consider whether their

child’s preoperative experience was improved in comparison to

prior experiences. For 14 of the 18 children, their parents con-

sidered the preoperative experience that included fluid intake up

to 120 minutes before surgery better than previous preoperative

episodes while the remaining four parents had no opinion.

• Vomiting

Six trials noted the occurrence of vomiting over the preopera-

tive period (Goresky 1992a; Goresky 1992b), on induction (Aun

1990; Maekawa 1993a; Maekawa 1993b; Schreiner 1990), intra-

operatively and on recovery (Aun 1990). Only eight children were

reported as having vomited preoperatively following the intake of

the fluid or fluid and medication intervention across two related

comparisons (Goresky 1992a; Goresky 1992b). It is not clear to

which groups these children belonged. No other vomiting inci-

dent was reported by the remaining four trials. These details are

presented in Table 18 Shortened Fluid Fast versus Standard Fast -

Vomiting.

Comparison 02: Duration - short solid and fluid fast versus

standard fast

Two trials compared a fasting regimen that permitted a shorter fast

from solid food and fluids to a standard fasting regimen (Meakin

1985b; Meakin 1985f). These trials will be presented below in re-

lation to (01) the incidence of aspiration/regurgitation, (02) gastric

contents - volume, and (03) gastric contents - pH. The secondary

outcomes of children’s thirst, hunger, behaviour, comfort, nausea

or vomiting were not considered by these trials. An overview of

the results in relation to a shortened solid and fluid fast is available

at the end of the results section.

Outcome 01: Aspiration/RegurgitationMeakin 1985b and Meakin 1985f report no incidence of regur-

gitation, aspiration, related morbidity or mortality was observed

during these comparisons. This information is presented in Table

12 Duration of Fast - Aspiration/Regurgitation in the additional

tables section.

Outcome 02: Gastric Contents - Volume(i) Solids and Fluids up to 120 minutes preoperatively versus Stan-

dard Fast

Meakin 1985b used a quasi-randomised approach (randomisation

by operation list) to allocate children to either a standard fast (n =

20) or to a fasting regimen that permitted the intake of two plain

biscuits and a drink of orange squash [10 ml/kg max 200 ml] up

to two hours preoperatively (n = 32). Pseudo-standard deviation

values were calculated and included within Comparison 02 Du-



ration - Short Solid Fast and Fluids versus Standard Fast, 01 Gas-

tric Contents - Volume. The children permitted solids and fluids

up to 120 minutes preoperatively had a significantly higher mean

volume of intra-operative gastric contents than those children that

fasted in the usual manner (WMD 0.25 ml/kg 95% CI 0.07 to

0.43) (p = 0.006).

It is also of note that particles of the solid food intervention were

observed in the gastric aspirate of 13 children permitted solid and

fluid intake while no particles were observed in the aspirate of

the fasted group (see Table 11). This significant result however is

based on a small number of children in a single quasi-randomised

trial.

(ii) Solids and Fluids up to 240 minutes preoperatively versus

Standard Fast

Meakin 1985f asked some children to eat two plain biscuits and

drink orange squash [10 ml/kg max 200 mls] up to four hours

preoperatively (n = 14) while the second group continued to fast

(n = 20). The results of this quasi-randomised trial are presented

in Comparison 02 Duration - Short Solid and Fluid Fast versus

Standard Fast, 01 Gastric Contents - Volume and pseudo-sum-

mary statistics were calculated. There was no indication of a dif-

ference between the groups’ intra-operative volume of gastric con-

tents (WMD 0.09 ml/kg 95% CI -0.12 to 0.30). Particles of food

were observed in the aspirate of three of the group permitted solids

and fluids but none of the fasted group (Table 11).

Outcome 03: Gastric Contents - pH(i) Solids and Fluids up to 120 minutes preoperatively versus Stan-

dard Fast

One trial evaluated the intake of solids and fluids up to 120 min-

utes preoperatively (Meakin 1985b). Children either followed a

standard fasting regimen (n = 14) or were permitted two plain

biscuits and a drink of orange squash [10 ml/kg max 200 mls]

(n = 29). Pseudo-mean and pseudo-standard deviations were cal-

culated and the quasi-randomised trial is presented in Compari-

son 02 Duration - Short Solid Fluid Fast versus Standard Fast, 02

Gastric Contents - pH. There was no indication of a difference

between the groups’ intra-operative gastric pH (WMD 0.35 95%

CI -0.08 to 0.78) however this comparison is extremely under-

powered.

(ii) Solids and Fluids up to 240 minutes preoperatively versus

Standard Fast

Similarly, Meakin 1985f quasi-randomised some children to re-

ceive two biscuits and a drink of orange squash [10 ml/kg max

200 mls] (n = 10) up to 240 minutes preoperatively. The intra-

operative gastric pH values were then compared with those of a

standard preoperative fast group (n = 14). Again, pseudo-mean

and pseudo-standard deviation values were required. Details of

this trial can be referred to in Comparison 02 Duration - Short

Solid Fluid Fast versus Standard Fast, 02 Gastric Contents - pH.

There was no indication of a difference between the groups’ intra-

operative gastric pH (WMD 0.11 95% CI -0.13 to 0.35).

Comparison 03: Duration - short solid and fluid fast versus

short fluid fast

Three trials compared a short solid and fluid fast with a shortened

fluid fast (Kushikata 1996; Meakin 1985c; Meakin 1985d). The

outcomes of these trials will be presented below in relation to (01)

the incidence of aspiration/regurgitation (02) volume of gastric

contents, (03) pH of gastric contents and the secondary outcomes.

No trial that compared a short solid and fluid fast with a short fluid

fast measured gastric volume using a marker dye. An overview of

the results is available at the end of the results section.

Outcome 01: Aspiration/regurgitationInformation on the incidence of aspiration and regurgitation was

available from two trials (n = 95). In the Meakin 1985c trial all chil-

dren were permitted an orange drink preoperatively (10 ml/kg up

to a maximum of 200 ml) and some children were also given two

plain biscuits up to two hours preoperatively. In Meakin 1985d

children received similar interventions but up to 4 hours preop-

eratively. There was no reported occurrence of regurgitation, as-

piration or any related morbidity or mortality. See Table 12 for

details.

Outcome 02: Gastric Contents - VolumeThree small trials compared a short solid and fluid fast to a short

fluid fast by measuring children’s gastric content volume. See Com-

parison: 03 Duration - Short Solid and Fluid Fast versus Short

Fluid Fast; Outcome 02 Gastric Contents - Volume for details.

(i) Solids and Fluids versus Fluids up to 120 minutes preoperatively

Meakin 1985c asked the children to drink 10 ml/kg [max 200 ml]

of an orange drink (n = 35) while some children were, in addition,

quasi-randomised to eat two plain biscuits up to 120 minutes

preoperatively (n = 32). There was no indication of difference in

intra-operative gastric volume (WMD 0.09 ml/kg 95% CI -0.08

to 0.26). Particles of the food intervention were observed in the

gastric aspirate of 13 of the children that were given solids and

fluid and none were noted in the aspirate of those permitted fluids

(Table 11).

(ii) Solids and Fluids versus Fluids up to 240 minutes preopera-

tively

Similarly, Meakin 1985d permitted children 10 ml/kg [max 200

ml] of an orange drink while some of the individuals were also

quasi-randomised to solid intake of two plain biscuits up to 240

minutes preoperatively. Again, there was no evidence of a differ-

ence in gastric volume regardless of whether they had taken solids

and fluids (n = 14) or fluids alone (n = 15) (WMD 0.04 ml/kg

95% CI -0.18 to 0.26). The authors report evidence of food par-

ticles in three children’s gastric aspirate and all three children were

in the group permitted solid fluid intake (Table 11).

(iii) Solids and Fluids versus Fluids up to 330 minutes preopera-

tively

The children in a third quasi-randomised trial were permitted clear

fluids [less than 200 ml] up to 300 minutes preoperatively while



half the group were allocated to a regimen that also permitted the

intake of rice porridge [55g rice + 245 ml water + salt] up 330

minutes preoperatively (Kushikata 1996). There was no difference

in the gastric content volume (WMD 0.12 ml/kg 95% CI -0.30 to

0.54). No particles were observed in the children’s gastric samples

(Table 11).

Outcome 03: Gastric Contents - pHThe three trials that compared a short solid and fluid fast to a

short fluid fast by measuring gastric content volume also measured

intra-operative gastric pH. Details of these quasi-randomised trials

can be referred to in Comparison 03 Duration - Short Solid and

Fluid Fast versus Standard Fast, 03 Gastric Contents - pH.

(i) Solids and Fluids versus Fluids up to 120 minutes preoperatively

Meakin 1985c gave children 10 ml/kg [max 200 ml] of an orange

drink (n = 31) while approximately half the children were also

given two plain biscuits up to 120 minutes preoperatively (n = 29).

There was no indication of difference in intra-operative gastric

pH of the children permitted solids and fluids and those only

permitted fluids (WMD 0.06, 95% CI -0.57 to 0.69).

(ii) Solids and Fluids versus Fluids up to 240 minutes preopera-

tively

A second small quasi-randomised trial asked children to drink 10

ml/kg [max 200 ml] of an orange drink while some of the children,

in addition, ate two plain biscuits up to 240 min preoperatively

(Meakin 1985d). There was no evidence of a difference in gastric

pH regardless of whether they had taken solids and fluids (n = 10)

or fluids alone (n = 12) (WMD 0.18, 95% CI -0.13 to 0.49).

(iii) Solids and Fluids versus Fluids up to 330 minutes preopera-

tively

Children in the Kushikata 1996 trial were quasi-randomised either

to a fast that permitted the intake of rice porridge up to 330

minutes preoperatively (n = 10) or to continue a standard fasting

regimen (n = 10). The rice porridge consisted of 55 g rice + 245 ml

water + salt. There was no evidence of a difference in intraoperative

gastric pH (WMD 0.46, 95% CI -0.03 to 0.95).

Secondary OutcomesKushikata 1996 also compared a shortened solid fast to a standard

fast by considering the children’s hunger. Hunger was recorded

on a three point scale (satisfied, moderate, very hungry) after they

had either followed a standard fast or after they had eaten rice

porridge and drank clear fluids (less than 200 ml) up to 330 min-

utes preoperatively. It is unclear whether the children or the re-

searchers completed the evaluation. The children permitted solid

intake were found to be less hungry than the children permitted

fluids alone. Details can be referred to in Table 19 Short Solid and

Fluid Fast versus Short Fluid Fast - Hunger. The additional sec-

ondary outcomes of thirst, behaviour, comfort or vomiting were

not considered.

Comparison 04: Duration - short fluid fast 1 versus short fluid

fast 2

Seven trials compared two different shortened fluid fasting reg-

imens i.e. both fasting regimens permitted the intake of fluids

nearer to the time of surgery than a traditional standard fast

(Cook-Sather 2003; Maekawa 1993c; Splinter Schaefer 1a; Splin-

ter Schaefer 1b; Splinter Schaefer 3a; Splinter Schaefer 3b; Splin-

ter Schaefer 3c) The evidence is presented in relation to the (i)

incidence of aspiration/regurgitation (ii) children’s gastric content

volume, (iii) gastric content pH and (iv) the secondary outcomes

of hunger, behaviour and vomiting. Gastric marker dye was not

considered as an outcome measure, nor were the secondary out-

comes of thirst, comfort or nausea.

Outcome 01: Aspiration/regurgitationNo regurgitation or aspiration was observed during three trials that

compared a short fluid fast to an even shorter fluid fast (Cook-

Sather 2003; Splinter Schaefer 1a; Splinter Schaefer 1b). In addi-

tion, Maekawa 1993c reported there was no coughing or laryn-

gospasm during their trial. This information is presented in more

detail in Table 12 Duration of Fast - Aspiration/Regurgitation.

Outcome 02: Gastric Contents - VolumeSeven trials compared the effects of two short fluid fasts on gastric

content volume on induction of anaesthesia (Cook-Sather 2003;

Maekawa 1993c; Splinter Schaefer 1a; Splinter Schaefer 1b; Splin-

ter Schaefer 3a; Splinter Schaefer 3b; Splinter Schaefer 3c). The

results of these comparisons can be referred to in Comparison: 04

Duration - Short Fluid Fast 1 versus Short Fluid Fast 2; Outcome

02 Gastric Contents - Volume.

(i) Fluids up to 120 minutes versus 150 minutes preoperatively

Splinter Schaefer 3c randomly permitted children unlimited in-

take of clear fluids up to 120 minutes (n = 50) or 150 minutes (n

= 50) preoperatively. There was no evidence of a between group

difference in the volume of gastric contents collected (WMD 0.06

ml/kg, 95% CI -0.05 to 0.17).

(ii) Fluids up to 120 minutes versus 180 minutes preoperatively

Two trials compared the unlimited intake of clear fluids up to

120 minutes (n = 124) with 180 minutes (n = 124) preoperatively

(Splinter Schaefer 1b; Splinter Schaefer 3a). Again, there was no

evidence of a difference in volume of gastric contents (WMD 0.04

ml/kg, 95% CI -0.08 to 0.15).

(iii) Fluids up to 120 minutes versus up to 240 minutes preoper-

atively

Two short fluid fasts were compared by an additional two trials

(Cook-Sather 2003; Maekawa 1993c). Children were either per-

mitted fluids up to 120 minutes (n = 71) or 240 minutes preoper-

atively (n = 66). In Maekawa 1993c both groups of children were

required to drink apple juice [10 ml/kg] while in the Cook-Sather

trial children in the shorter fasting group (120 minutes preop-

eratively) were permitted clear fluids and the second group were

permitted formula up to 240 minutes preoperatively. There was

no difference in (WMD 0.00 ml/kg, 95% CI -0.13 to 0.13). The

gastric aspirate of nine of the children in Cook-Sather 2003 was



found to have evidence of formula (eight were tinged white and

one clear aspirate contained small particles). One of these children

had fasted (excluding the intervention) for a total of 10 hours (Ta-

ble 11 for details).

(iv) Fluids up to 150 minutes versus up to 180 minutes preoper-

atively

Splinter Schaefer 1a and Splinter Schaefer 3b compared the in-

take of unlimited clear fluids up to 150 (n = 90) and 240 minutes

preoperatively (n = 90). On pooling the data there was no statisti-

cally significant difference between the two groups’ gastric volume

(WMD -0.04 ml/kg 95% CI -0.16 to 0.09).

Outcome 03: Gastric Contents - pHThe intra-operative volume of children’s gastric pH was used to

compare two short fluid fasts in seven trials (Cook-Sather 2003;

Maekawa 1993c; Splinter Schaefer 1a; Splinter Schaefer 1b; Splin-

ter Schaefer 3a; Splinter Schaefer 3b; Splinter Schaefer 3c). The

results of these comparisons can be referred to in Comparison: 04

Duration - Short Fluid Fast 1 versus Short Fluid Fast 2; Outcome

03 Gastric Contents - pH.

(i) Fluids up to 120 minutes versus up to 150 minutes preopera-

tively

Splinter Schaefer 3c compared the unlimited intake of clear fluids

up to 120 minutes (n = 50) or 150 minutes (n = 50) preoperatively

by comparing gastric pH. There was no evidence of a between

group difference (WMD 0.10, 95% CI -0.41 to 0.61).

(ii) Fluids up to 120 minutes versus up to 180 minutes preopera-

tively

The two trials that compared the unlimited intake of clear fluids

up to 120 minutes (n = 124) and up to 180 minutes (n = 124)

preoperatively by measuring gastric volume also measured gastric

pH (Splinter Schaefer 1b; Splinter Schaefer 3a). On pooling the

data there was no evidence of a difference in intra-operative gastric

pH (WMD 0.12, 95% CI -0.36 to 0.61).

(iii) Fluids up to 120 minutes versus up to 240 minutes preoper-

atively

Maekawa 1993c and Cook-Sather 2003 compared two short fluid

fasts using the outcome measure gastric pH. Children drank apple

juice [10ml/kg] up to 120 minutes or 240 minutes preoperatively

in one trial (Maekawa 1993c) while the children in the other

trial (Cook-Sather 2003) were permitted clear fluids up to 120

minutes or formula up to 240 minutes preoperatively. There was

no difference in intra-operative gastric pH (WMD 0.13, 95% CI

-0.33 to 0.60).

(iv) Fluids up to 150 minutes versus up to 180 minutes preoper-

atively

Splinter Schaefer 1a and Splinter Schaefer 3b compared the intra-

operative gastric pH of children permitted unlimited intake of

clear fluids up to 150 minutes (n = 90) and up to 180 minutes (n

= 90) preoperatively. There was no evidence of a difference in pH

(WMD 0.19, 95% CI -0.12 to 0.50).

Secondary OutcomesTwo of the trials that compared a short fluid fast with a very short

fluid fast, also measured hunger, behaviour or vomiting (Cook-

Sather 2003; Maekawa 1993c). Cook-Sather 2003 asked parents

to rate their child’s hunger and behaviour (irritability) on a VAS

after the child had left for the operating room. The children had

either been permitted clear fluids up to 120 minutes preoperative

or formula up to 240 minutes preoperatively. There was no appar-

ent difference between the two group’s observed hunger (Table 20)

or behaviour (Table 21). Vomiting was not observed amongst the

children in either the Cook-Sather 2003 nor the Maekawa 1993c

trials (Table 22 for details).

B. Type of permitted intake

The type of intake permitted prior to a child’s surgery has been

a clinical consideration for many years. The variety of milk feeds

(breast milk, formula milk, cows’ milk) and other drinks available

and consumed by children raises the issue of what the evidence is

in relation to type of intake permitted during a restricted fasting

period. As outlined within the protocol, two subgroup analyses

were conducted which examined the Comparison 05 Fluid Intake

Permitted versus Standard Fast and Comparison 06 Fluid 1 versus

Fluid 2. Each analysis is presented in relation to the outcomes used

to measure the effectiveness of the experimental fasting regimens,

namely (01) aspiration/regurgitation (02) volume of gastric con-

tents, (03) pH of gastric contents, (04) marker dye measures of

gastric contents and secondary outcomes.

Comparison 05: Type of Intake - fluid versus standard fast

Outcome 01: Aspiration/RegurgitationInformation on the incidence of aspiration or regurgitation was

available in relation to 18 trials that compared a standard fasting

regimen to the intake of water, clear fluids, fruit juice, or other

fluids. Only one incidence of regurgitation and aspiration on in-

duction was reported. See Table 23 Type of Intake - Aspiration/

Regurgitation for details.

Outcome 02: Gastric Contents - VolumeTwenty-four trials compared a shortened fluid fast with a standard

fasting regimen and are grouped according to the type of intake

children were permitted prior to surgery. The categories include

water, clear fluids, fruit juice, milk, dextrose solutions and other

types of fluid intake. Pseudo-values were calculated for several trials

and these are detailed below. As a result, a conservative approach

to pooling these data was taken and a random effects model was

used. The results can be referred to in Comparison: 05 Type of

Intake - Fluid versus Standard Fast; Outcome 02 Gastric Contents

- Volume.

(i) Water versus Standard Fast

One trial (Gombar 1997) gave the children water (n = 25) during

a period of restricted intake and compared their gastric volume

with that of children after a standard fast (n = 25). There was no

evidence of a difference in gastric volume (WMD -0.04 ml/kg,

95% CI -0.16 to 0.08).



(ii) Other Clear Fluids versus Standard Fast

Five trials compared the effect of permitted intake of clear fluids

preoperatively (n = 257) and a standard fast (n = 284) on gas-

tric content volume (Nicolson 1992; Sarti 1991; Schreiner 1990;

Splinter 1991; Splinter Schaefer 2). There was little heterogene-

ity (I2 = 7%) and no evidence of a difference in volume of intra-

operative gastric contents (WMD -0.02 ml/kg, 95% CI -0.09 to

0.05).

(iii) Dextrose Solution (five percent) versus Standard Fast

Three trials administered a drink of five percent dextrose solution

to 58 children while an additional 52 children continued to fast

(Aun 1990; Miller 1990; van der Walt 1986b). Psuedo-values were

calculated for two of the trials (Aun 1990; van der Walt 1986b)

and wide confidence intervals were observed especially in relation

to the Aun data. On pooling the data there was no indication of

a difference in intra-operative volume of gastric contents (WMD

-0.14 ml/kg, 95% CI -0.43 to 0.15).

(iv) Fruit Juice versus Standard Fast

Children’s gastric volume following the intake of fruit juice (n =

226) and following a standard fast (n = 168) was compared in eight

trials (Goresky 1992a; Maekawa 1993a; Maekawa 1993b; Sand-

har 1989a; Splinter 1989; Splinter 1990a; Splinter 1990b; Wel-

born 1993). Pseudo-values were calculated for two trials (Sand-

har 1989a; Welborn 1993) and included within the meta-analysis

while the Goresky 1992a trial did not report the separate group

summary data and therefore could not be included within the

meta-analysis. On pooling the data there was no evidence of a dif-

ference in volume of intra-operative gastric contents (WMD 0.02

ml/kg, 95% CI -0.08 to 0.11).

(v) Fruit Juice versus Standard Fast (+ H2-receptor antagonist)

Sandhar 1989b and Goresky 1992b also measured gastric content

volume in order to compare children’s preoperative intake of fruit

juice to a standard fast. Ranitidine was also administered to all

children as a preoperative co-intervention. Goresky 1992b how-

ever, did not report separate group summary data and so could not

be included within the meta-analysis. Pseudo- mean and standard

deviation values were calculated for Sandhar 1989b data. There

was no evidence of a between group difference in gastric volume

(WMD 0.01 ml/kg, 95% CI -0.11 to 0.13).

(vi) Milk versus Standard Fast

Only one trial (van der Walt 1986c) compared the preoperative

intake of cow’s milk during a shortened fluid fast (n = 31) with

a standard fasting regimen (n = 33). Pseudo-values were required

to allow presentation of the trial in the graph though there was

no evidence of a between group difference in the children’s gastric

volume (WMD 0.08 ml/kg, 95% CI -0.29 to 0.45).

(vii) Other Fluids versus Standard Fast

Four trials compared the intake of a variety of other fluids during a

preoperative fast (n = 100) with a standard fasting regimen (n = 56)

by measuring the volume of children’s intra-operative gastric con-

tents. Fluids permitted included poly-joule (van der Walt 1986a),

orange squash (Meakin 1985a; Meakin 1985e) and an isosmolar

solution of electrolytes (Moyao-García 2001). Pseudo-values were

required for van der Walt 1986a. The confidence intervals noted,

however, are wide and scattered and there is evidence of hetero-

geneity (p = 0.002).

Outcome 03: Gastric Contents - pHA total of 24 trials measured the pH of children’s gastric contents

and compared preoperative fluids with a fast in the standard man-

ner. Trials permitted the intervention group to drink water (i),

other clear fluids (ii), dextrose solution (iii), fruit juice (iv and v),

cows’ milk (vi) and a variety of other fluids (vii). The data was

pooled using a random effects model and details can be referred

to in Comparison 05 Type of Intake - Fluid versus Standard Fast;

Outcome 03 Gastric Contents - pH.

(i) Water versus Standard Fast

Only Gombar 1997 compared the preoperative intake of water (n

= 24) with a standard fast (n = 25) by measuring the children’s

gastric pH. There was no indication of a difference in gastric pH

(WMD 0.27, 95% CI -0.12 to 0.66).

(ii) Other Clear Fluids versus Standard Fast

Five trials permitted some children to drink a variety of clear flu-

ids preoperatively (n = 220) while the remaining children were

fasted (n = 235). Pseudo-standard deviation values were required

for Schreiner 1990. With all five trials presenting relatively nar-

row confidence intervals the results provide little indication of an

important clinical difference between the two groups’ gastric pH

values (WMD 0.09, 95% CI -0.03 to 0.21).

(iii)Dextrose Solution (five percent) versus Standard Fast

Drinking a dextrose solution preoperatively (n = 34) was compared

to a standard fasting regimen (n = 31) by two trials (van der Walt

1986b; Miller 1990). An additional trial (Aun 1990) also made

this comparison but group specific data in relation to the children’s

gastric pH was unavailable. Pseudo-values were required for van

der Walt 1986b. There was no indication of a difference between

gastric pH of children given dextrose and those who fasted (WMD

-0.51, 95% CI -2.21 to 1.19).

(iv) Fruit Juice versus Standard Fast (no H2-receptor antagonist)

The eight trials that compared the effect on gastric volume of fruit

juice (n = 255) and a standard fast (n = 200) also measured the

children’s gastric pH. To permit inclusion within the meta-analy-

sis pseudo-standard deviation values were calculated for Sandhar

1989a and Welborn 1993. On pooling the data, there was no in-

dication of a difference between the group’s intra-operative gastric

pH (WMD 0.04, 95% CI -0.01 to 0.10).

(v) Fruit Juice versus Standard Fast (+ H2-receptor antagonist)

Two trials (Goresky 1992b; Sandhar 1989b) compared the pre

operative intake of fruit juice (n = 68) with a standard fasting

regimen (n = 61). Both trials also administered a H2-receptor

antagonist co-intervention. Pseudo-standard deviation values were



calculated for Sandhar 1989b and there was no indication of a

difference in gastric pH (WMD 0.53, 95% CI -0.19 to 1.26).

(vi) Milk versus Standard Fast

The gastric pH of children who were permitted cows’ milk pre-

operatively and those who fasted were compared in van der Walt

1986c. Pseudo-values were calculated to allow presentation within

the meta-analysis. There was no indication based on this small

trial that the intake of milk up to three hours preoperatively had

any impact on intra-operative gastric pH (WMD -0.01, 95% CI

-1.82 to 1.80).

(vii) Other Fluids versus Standard Fast

Four trials evaluated the intake of a range of other fluids during a

preoperative fast by measuring the children’s intra-operative gastric

pH. Fluids permitted included poly-joule (a mixture of glucose

polymers - maltodextrin) (van der Walt 1986a), orange squash

(Meakin 1985a; Meakin 1985e) and an isosmolar solution of elec-

trolytes (Moyoa-Garcia 2001). Pseudo-mean and standard devi-

ation values were calculated for three trials (van der Walt 1986a;

Meakin 1985a; Meakin 1985e). The trial results indicate widely

scattered confidence intervals (see in particular van der Walt 1986a

and Moyao-García 2001) which at present provide insufficient ev-

idence to state whether or not an important difference exists be-

tween the groups permitted fluids (n = 80) and those that fasted

(n = 41) (WMD 0.34 95% CI -0.62 to 1.31).

Outcome 04: Gastric Contents - Marker DyeThe marker dyes phenol red and bromosulphthalein were used by

five trials as a means of comparing a fasting regimen that permitted

fluid intake with a prolonged fast. The results will be presented

below in relation to the marker dye used and the type of fluid

permitted during the restricted fasting period.

Phenol red

(i) Fruit Juice versus Standard Fast

Sandhar 1989a and Sandhar 1989b used phenol red to compare

the intake of orange juice up to 120 minutes preoperatively with

a standard fast. Sandhar 1989b also administered a ranitidine co-

intervention to all children. One child in the Sandhar 1989a trial

who had fasted for an hour since the placebo intervention was

found to have a 33% percent dye retrieval. Dye retrieval for the

remaining children was less than five percent and for many children

no dye was found. In the Sandhar 1989b trial dye retrieval was

12% for one child (juice and ranitidine intervention) that fasted

for one hour while the remaining children had a dye retrieval of

less than five percent.

(ii) Dextrose Solution (five percent) versus Standard Fast

Miller 1990 used phenol red to compare the effect on gastric vol-

ume of a dextrose solution drink (n = 19) with no fluid intake (n

= 25). The results are reported as ml and details can be referred to

in Comparison 05 Type of Fluid Intake versus Standard Fast 04

Gastric contents - Phenol Red based volume (ml). There was no

evidence of a between group difference in the marker dye based

measure of intraoperative gastric volume (WMD -3.10 ml, 95%

CI -6.66 to 0.46).

Bromosulphthalein

(i) Fruit Juice versus Standard Fast

The dye bromosulphthalein was used by two trials to evaluate

the contribution fluids ingested during a restricted fasting period

made to children’s intra-operative gastric volume. Results were

reported as a percentage of recovered dye. Goresky 1992a and

Goresky 1992b compared the preoperative intake of orange juice

with a standard fast. Goresky 1992b also asked children to take

a ranitidine (H2 receptor antagonist) co-intervention. Separate

group data were not available. It was reported however, that the

dye recovered from those children who were permitted to drink

during the preoperative period represented less than 0.3% of the

volume of intake at the time of marker dye administration. The

researchers also noted that more dye was recovered from those

children given ranitidine than those that did not receive this drug

(p < 0.001). Additional details were unavailable.

Secondary OutcomesReports of thirst, hunger, behaviour, comfort and vomiting were

noted by thirteen trials that compared the intake of a variety of

fluids with a standard fast. No trial measured nausea. An overview

of these trials and the measures used can be referred to in Table

24 Type of Intake - Secondary Outcome Measures. These results

are presented below.

• Thirst

Thirst was measured in six different trials that compared the in-

take of a preoperative fluid to a standard fast. All trials used a VAS

(Splinter 1989 used two) and measures were taken either prein-

duction (time point f ) or after the child had left for surgery (time

point g - see Table 10). The children permitted water or clear

fluids preoperatively described significantly less thirst than those

who fasted (Gombar 1997; Nicolson 1992; Splinter 1991). Sim-

ilarly, the trials that evaluated pre operative apple juice found the

children (or parents of children) permitted apple juice recorded

significantly less thirst on the VAS than the children who fasted

(Splinter 1990a; Splinter 1989). Splinter 1989 and Splinter 1990b

found no difference between the children’s description of thirst.

Details can be seen in Table 25 Type of Fluid versus Standard Fast

- Thirst.

This indicates an interesting difference between the trials that eval-

uated the administration of apple juice preoperatively (Splinter

1989; Splinter 1990a; Splinter 1990b). All three recruited chil-

dren aged 5-10 years and randomly allocated them to receive ap-

ple juice up to 150 minutes preoperatively or to the standard fast-

ing regimen. The only obvious difference between these trials re-

lates to the volume of intake permitted which varied from 3ml/kg

(Splinter 1989), 6ml/kg (Splinter 1990a) and 10ml/kg (Splinter

1990b). The issue of volume of intake will be dealt with in more

detail below.



• Hunger

Five trials measured children’s hunger in a comparison of a fast

that permitted the intake of clear fluids (Nicolson 1992; Splin-

ter 1991) or apple juice (Splinter 1989; Splinter 1990a; Splinter

1990b) to a standard fasting regimen. Descriptions of hunger were

made by either the children themselves (Splinter 1989; Splinter

1990a; Splinter 1990b; Splinter 1991) and/or their parents (Nicol-

son 1992; Splinter 1989). All respondents used VAS to measure

children (or parent’s) ratings of preoperative hunger with measures

taken pre-induction or after the child had left for surgery. Parental

reports indicated that the children permitted clear fluids or apple

juice were less hungry than those that continued to fast (Nicolson

1992; Splinter 1989). Based on children’s report, only one of the

trials that permitted preoperative apple juice described less hunger

than those that fasted (Splinter 1989). In the remaining trials that

administered either preoperative clear fluids (Splinter 1991) or ap-

ple juice (Splinter 1990a; Splinter 1990b) while the control group

fasted, there was no difference between the children’s descriptions

of hunger. Details are presented in Table 26 Type of Fluid versus

Standard Fast - Hunger.

• Behaviour

Behaviour was measured by four trials that compared the preoper-

ative intake of water, clear fluids and apple juice to a standard fast-

ing regimen. In all cases parents rated their children’s behaviour in

terms of irritability on a VAS immediately prior to surgery or after

the child had left for surgery. In three of the four trials children

permitted water (Gombar 1997), clear fluids (Schreiner 1990) and

apple juice (Splinter 1990a) were rated by their parents as less ir-

ritable when compared to the ratings made by the parents of chil-

dren who fasted. Splinter 1990b however, found no difference in

the parents’ report of the behaviour amongst children permitted

apple juice preoperatively and those that fasted. See details in Ta-

ble 27 Type of Fluid versus Standard Fast - Behaviour.

• Comfort

Nicolson 1992 and Schreiner 1990 measured parents’ perceptions

of their child’s comfort using VAS. Both trials found that the

parents of children permitted clear fluids preoperatively described

their children as more comfortable (or as having tolerated the

experience better) than the children who followed a standard fast.

Details can be referred to in Table 28 Type of Fluid versus Standard

Fast - Comfort.

• Vomiting

The incidence of vomiting amongst children was reported in

six trials that evaluated the preoperative intake of clear fluids

(Schreiner 1990), apple juice (Goresky 1992a; Goresky 1992b;

Maekawa 1993a; Maekawa 1993b) and a dextrose solution (Aun

1990). Only Goresky 1992a and Goresky 1992b reported any

vomiting but these incidents appear to be linked to vomiting of

the preoperative intervention (apple juice [5 ml/kg] and placebo/

ranitidine [2 mg/kg]) rather than vomiting on immediately pre-

or post-induction. The report also does not report how many of

this group (n = 8) vomited, gagged or spat out the intervention,

nor is it clear to which group these children belonged. See Table

29 Type of Fluid versus Standard Fast - Vomiting for details.

Comparison 06: Type of intake - fluid 1 versus fluid 2

Three related trials directly compared the preoperative intake of

two different types of fluids during a shortened fluid fast. The

outcomes measured included (01) aspiration/regurgitation, (02)

the volume and (03) pH of children’s gastric contents. Marker

dye measures and secondary outcomes (thirst, hunger, behaviour,

comfort, nausea or vomiting) were not considered by any of these

trials.

Outcome 01: Aspiration/RegurgitationThe three trials that compared the intake of a dextrose solution

with Polyjoule (van der Walt 1986d), dextrose solution with cows’

milk (van der Walt 1986e) and Poly joule with cows’ milk (van

der Walt 1986f ) reported the incidence of aspiration and regur-

gitation observed within their trials. No significant aspiration or

other drink-related complications were observed. For details see

Table 23 Type of Intake - Aspiration/Regurgitation.

Outcome 02: Gastric Contents - VolumeTrials that compared the effects on intraoperative gastric volume

of two different types of preoperative fluid intake are presented

within this section. Pseudo-mean and standard deviation values

were calculated for all three trials. The trials are presented in Com-

parison: 06 Type of Intake - Fluid 1 [F1] versus Fluid 2 [F2]; Out-

come 02 Gastric Contents - Volume.

(i) Dextrose solution versus Polyjoule

van der Walt 1986d compared the preoperative intakes of five

percent dextrose solution (n = 29) with Polyjoule (maltodextrin)

(n = 30) by measuring children’s gastric volume during surgery.

There was no indication of a difference between the two groups’

gastric volume (WMD 0.03 ml/kg, 95% CI -0.15 to 0.21).

(ii) Dextrose solution versus Cows’ milk

The preoperative intake of five percent dextrose solution (n = 29)

was compared with the intake of cows’ milk (n = 31) in van der

Walt 1986e. A significantly lower volume of gastric contents was

recovered from the children who drank the dextrose solution than

those who were given cows’ milk (WMD -0.44 ml/kg, 95% CI

-0.75 to -0.13) (p = 0.005). This significant result however is based

on a small number of children within a single trial.

(iii) Poly joule versus Cows’ milk

In a third comparison, van der Walt 1986f compared the effect on

gastric volume of Polyjoule (n = 30) and cows’ milk (n = 31). There

was a significantly lower gastric volume in the children who drank

Polyjoule than those who drank cows’ milk (WMD -0.47ml/kg,

95% CI -0.78 to -0.16) (p = 0.005) but this result is based on a

very small number of children within a single trial.

Outcome 03: Gastric Contents - pH



All three trials that compared the effect on gastric volume of the

intake of two different fluids during the preoperative period also

measured the gastric pH. Pseudo-mean and standard deviation

values were calculated and a random effects model was used to

present the data which can be referred to in Comparison: 06 Type

of Intake - Fluid 1 versus Fluid 2; Outcome 03 Gastric Contents

- pH.

(i) Dextrose solution versus Polyjoule

The preoperative intake of five percent dextrose solution (n = 29)

and Polyjoule (n = 30) were compared by van der Walt 1986d.

There was no indication of a difference in intra-operative gastric

pH (WMD -0.75, 95% CI -1.62 to 0.12).

(ii) Dextrose solution versus Cows’ milk

Similarly, van der Walt 1986e measured gastric pH after preop-

erative intake of 5% dextrose (n = 29) and cows’ milk (n = 31).

The children who drank dextrose had significantly higher gastric

acidity than those who drank cows’ milk (WMD -1.74 95% CI

-3.09 to -0.39) (p = 0.01). This significant result is in contrast to

the result in relation to children’s gastric volume which was lower

after dextrose. However, both results should be considered in light

of the very small number of children this one trial was based on.

(iii) Poly joule versus Cows’ milk

Polyjoule (n = 30) and cows’ milk (n = 31) were compared in

relation to gastric pH and there was no evidence of a difference

between the two groups (WMD -1.01, 95% CI -2.49 to 0.47)(van

der Walt 1986f ).

For summary of Type of Permitted Intake Results - see end of

results section.

C. Volume of permitted intake

While very small volumes of fluids are usually permitted during

the preoperative period (for example up to 30 ml to allow the in-

take of medication) many clinicians question whether higher vol-

umes of fluids could be permitted during this period. A total of 25

trials are presented in this section in relation to the volume of in-

take permitted during a period of restricted intake. Comparisons

were either made between several different volumes of intake and

a standard fasting regimen, or between two different volumes of

intake. For analysis purposes the various volumes permitted pre-

operatively were categorised into three types of intake; low vol-

ume (less than or equal to 5 ml/kg), high volume (more than 5

ml/kg) and unlimited volumes (where no restriction was placed

on the volume of children’s preoperative fluid intake). As outlined

at the protocol stage, two subgroup analyses were conducted to

examine Comparison 07 Volume of Intake versus Standard Fast

and Comparison 08 Volume 1 versus Volume 2. For each analysis

the outcome measures (01) aspiration/regurgitation, (02) volume

of gastric contents, (03) pH of gastric contents, (04) marker dye

measures and secondary outcomes were considered.

Comparison 07 Volume of fluid versus standard fast

Outcome 01: Aspiration/Regurgitation

Eighteen trials made a specific report (either published or unpub-

lished) in relation to the incidence of aspiration and regurgitation

during an investigation which evaluated the intake of a volume

of fluid during a restricted fasting period. No aspiration or regur-

gitation was reported by any of the trials that compared the pre-

operative intake of unrestricted volumes of fluid (Nicolson 1992;

Schreiner 1990; Splinter Schaefer 2) or the intake of a high volume

of fluid (Aun 1990; Maekawa 1993a; Maekawa 1993b; Meakin

1985a; Meakin 1985b; Splinter 1990a; Splinter 1990b; van der

Walt 1986a; van der Walt 1986b; van der Walt 1986c) with a

standard fast. Of the five trials that compared the intake of a low

volume of fluids preoperatively with a standard fasting regimen

(Gombar 1997; Goresky 1992a; Goresky 1992b; Moyao-García

2001; Splinter 1989) only one incident of coughing and aspira-

tion on induction was observed by Goresky 1992a. The authors

of the trial suggest this event was related to airway management

rather than the intervention. Details can be referred to in Table

30 Volume of Intake - Aspiration/Regurgitation.

Outcome 02: Gastric Contents - VolumeA total of 23 trials compared the effect on gastric content volume

of different volumes of preoperative intake and a standard fasting

regimen. Wherever possible the data were pooled using a random

effects model and presented in Comparison: 08 Volume of Intake

- Volume of Fluid versus Standard Fast; Outcome 02 Gastric Con-

tents - Volume.

(i) Low Volume Fluid Intake versus Standard Fast

Four trials administered a volume of fluid less than or equal to 5

ml/kg to the children in the intervention group (n = 98) while

the other children continued to fast (n = 104) (Gombar 1997;

Moyao-García 2001; Sandhar 1989a; Splinter 1989). The volume

of fluids administered to the intervention groups included 3 ml/kg

of apple juice (Splinter 1989), 4 ml/kg of an isomolar solution of

electrolytes (Moyao-García 2001) and 5 ml/kg of water (Gombar

1997) and orange juice (Sandhar 1989a). Pseudo-standard devi-

ation values were required to allow the inclusion of the Sandhar

1989a trial within the meta-analysis. On pooling the data there

was no evidence of a difference in gastric content volumes between

the children who had a low volume of preoperative fluid intake

and those who fasted (WMD -0.12 ml/kg, 95% CI -0.29 to 0.05).

The pooled results are underpowered, there is high heterogeneity,

and do not exclude the possibility of a clinically important differ-

ence in favour of the intake of a low volume of fluids. The results

from Goresky 1992a could not be included in the meta-analysis

as no group specific data were available.

(ii) Low Volume Fluid Intake versus Standard Fast (+ H2-receptor

antagonist)

Two additional trials (Goresky 1992b; Sandhar 1989b) also com-

pared the effect on gastric volume of the intake of a low volume of

fruit juice (5ml/kg) and a standard fast. The children within these

trials also received ranitidine, a H2-receptor antagonist. Separate

group data for the Goresky 1992b trial however were unavailable



and so this trial could not be included within the meta-analysis.

Pseudo-standard deviation values were required to allow inclusion

of the Sandhar 1989b trial. There was no evidence of a difference

in gastric volume of children permitted a low volume of orange

juice (n = 18) and those who fasted in the usual manner (n = 15)

(WMD 0.01 ml/kg, 95% CI -0.11 to 0.13).

(iii) High Volume Fluid Intake versus Standard Fast

Eleven trials compared the effect on gastric volume of a high vol-

ume of fluids preoperatively (n = 323) and a standard fast (n = 172).

Children in the fluid group were permitted 6 ml/kg of apple juice

(Splinter 1990a), 10 ml/kg of dextrose solution (Aun 1990; van

der Walt 1986b), cows’ milk (van der Walt 1986c) Polyjoule (van

der Walt 1986a), orange squash (Meakin 1985a; Meakin 1985e)

or apple juice (Maekawa 1993a; Maekawa 1993b; Splinter 1990b;

Welborn 1993). Pseudo-mean and standard deviation values were

required for a number of trials (Aun 1990; Meakin 1985a; van der

Walt 1986a; van der Walt 1986b; van der Walt 1986c; Welborn

1993). The was no significant difference in gastric content volume

(WMD 0.04 ml/kg, 95% CI -0.05 to 0.13).

(iv) Unlimited Fluid Intake versus Standard Fast

Five trials permitted children in the experimental group to have

preoperative access to an unlimited volume of clear fluid (n = 257)

whilst the control groups underwent a standard fast (n = 284).

The duration of fast amongst the intervention groups ranged from

120 minutes (Nicolson 1992; Sarti 1991; Schreiner 1990) to 180

minutes (Splinter 1991; Splinter Schaefer 2). The fluid and fasted

groups’ volume of gastric contents were then compared. There

was no difference in intra-operative gastric volume (WMD -0.02

ml/kg, 95% CI -0.09 to 0.05).

Outcome 03: Gastric Contents - pHIntra-operative gastric pH was measured in 22 trials that compared

different volumes of preoperative intake with a standard fasting

regimen. Pseudo-values were calculated for some trials and a ran-

dom effects model was used to pool the data which can be referred

to in Comparison: 08 Volume of Intake - Volume of Fluid versus

Standard Fast; Outcome 03 Gastric Contents - pH.

(i) Low Volume Fluid Intake versus Standard Fast (no H2-receptor

antagonist)

Five trials compared the effect on gastric pH of a low volume of

fluid (n = 144) and a standard fasting regimen (n = 146). Hetero-

geneity was very high (I2 = 91%) and there is insufficient evidence

of an effect on gastric pH values (WMD 0.42, 95% CI -0.19 to

1.04).

(ii) Low Volume Fluid Intake versus Standard Fast (+ H2-receptor

antagonist)

Two trials compared the effect on gastric pH of a low volume of

preoperative fluid and a standard fast (Sandhar 1989b; Goresky

1992a). The children in these trials also received a H2 receptor an-

tagonist as a co-intervention. The data from Goresky 1992a could

not be included as the outcome measures were only reported as a

cross-group summary. Pseudo-mean and pseudo-standard devia-

tion values were calculated for Sandhar 1989b to allow inclusion

of the trial within the meta-analysis. There was no evidence of a

difference in gastric pH of those children given a low volume of

fluid (n = 68) and those who fasted (n = 61) (WMD 0.53, 95%

CI -0.19 to 1.26).

(iii) High Volume Fluid Intake versus Standard Fast

Children permitted a high volume of fluids (n = 244) and chil-

dren who were fasted in the standard manner (n = 126) were

compared by measuring the pH of their intra-operative gastric

contents. Ten trials gave children in the intervention group ei-

ther apple juice (Splinter 1990a; Splinter 1990b; Maekawa 1993a;

Maekawa 1993b; Welborn 1993), dextrose (Aun 1990; van der

Walt 1986b), cows’ milk (van der Walt 1986c), Poly joule (van der

Walt 1986a) or orange squash (Meakin 1985a; Meakin 1985e) at

volumes ranging from 6 ml/kg to 10 ml/kg. Pseudo-values were

required for five trials (Aun 1990; van der Walt 1986a; van der

Walt 1986b; van der Walt 1986c; Welborn 1993) to permit in-

clusion within the meta-analysis. The variance in the data from

the van der Walt study was large, although overall heterogeneity

was low (I2 - 0%) and using a random effects model, there was

insufficient evidence to indicate whether a difference between the

groups’ gastric pH existed (WMD 0.04, 95% CI -0.02 to 0.09).

(iv) Unlimited Fluid Intake versus Standard Fast

Children in the intervention groups of five trials (Nicolson 1992;

Sarti 1991; Schreiner 1990; Splinter 1991; Splinter Schaefer 2)

were permitted unlimited volumes of clear fluids or a choice be-

tween apple juice and water (Sarti 1991) during the preoperative

period (n = 220) while those in the study group continued to fast

(n = 235). There was little indication of an important clinical dif-

ference in gastric pH (WMD 0.09, 95% CI -0.03 to 0.21).

Outcome 04: Gastric Contents - Marker DyeFour trials compared the intake of a low volume of fluid with a

standard fasting regimen using the marker dyes phenol red and

bromosulphthalein.

Phenol red

Two trials used phenol red as a marker dye.

(i) Low Volume of Fluids versus Standard Fast

Sandhar 1989a and Sandhar 1989b used the marker dye to com-

pare low volume of orange juice preoperatively (n = 31) with a

standard fast (n = 34). Sandhar 1989b included a ranitidine co-

intervention. For many children in the Sandhar 1989a trial no dye

was found. One child who had fasted for an hour after the placebo

intervention, was found to have 33% percent dye retrieval. Sim-

ilarly, in the Sandhar 1989b trial, dye retrieval was 12% for one

child who had ingested a low volume of orange juice (plus raniti-

dine). The remaining children in both trials had a dye retrieval of

less than 5%.

Bromosulphthalein

Two trials used bromosulphthalein as a marker dye.



(i) Low Volume of Fluids versus Standard Fast

Goresky 1992a and Goresky 1992b used BSP to measure the con-

tribution of the ingested fluids to the intra-operative gastric vol-

ume. Results were reported as a percentage (%) of recovered dye.

Both trials compared the intake of a low volume of fluids (5 ml/kg)

with a standard fast but one included a ranitidine (H2receptor an-

tagonist) co-intervention (Goresky 1992b). Separate group sum-

mary data were unavailable and instead the results for the two

groups that followed a standard fast were combined and compared

to the recovered marker dye values from the combined group per-

mitted a low volume of fluids. Fluid intake was reported to have

had an insignificant effect on the dye recovery. The dye recovered

represented less than 0.3% of the volume of intake at the time of

marker dye administration. More dye was recovered from those

children given ranitidine than the children that did not receive

this co-intervention (p < 0.001). No other details were available.

Secondary Outcome MeasuresTwelve trials compared the preoperative intake of a low (less than

or equal to 5 ml/kg), high (over 5 ml/kg) or unlimited volume of

fluid preoperatively to a standard fasting regimen by measuring

children’s thirst, hunger, behaviour, comfort, or vomiting. No trial

attempted to measure children’s reports of nausea. Details of these

trials, the outcomes measured and the measurement tools used can

be referred to in Table 31 Volume of Intake - Secondary Outcome

Measures.

• Thirst

Children’s thirst was measured by six trials that compared a stan-

dard fasting regimen to one that permitted the preoperative intake

of a low, high or unlimited volume of fluid intake. In all cases, re-

ports of thirst were measured preoperatively using a VAS and were

completed by the child (Gombar 1997; Splinter 1989; Splinter

1990a; Splinter 1990b, Splinter 1991) or their parent (Nicolson

1992; Splinter 1989). Details can be referred to in Table 32 Vol-

ume of Fluid versus Standard Fast - Thirst. In all cases where a

statistically significant difference was noted, the children permit-

ted a low (Gombar 1997), high (Splinter 1990a) or unlimited vol-

ume of fluid (Splinter 1991) reported less thirst than the children

who fasted. Similarly, parents also described less thirst amongst

the children permitted a low (Splinter 1989) or unlimited fluid

intake (Nicolson 1992) than the parents of children who fasted.

Two trials found no difference in descriptions of thirst (Splinter

1989; Splinter 1990b).

• Hunger

Five trials compared the preoperative intake of a low (Splinter

1989), high (Splinter 1990a; Splinter 1990b) or unlimited vol-

ume of fluid (Nicolson 1992; Splinter 1991) with a standard

fast by measuring hunger. In most cases children were asked to

record their preoperative hunger on a VAS (Splinter 1989; Splin-

ter 1990a; Splinter 1990b; Splinter 1991) but two trials (Splinter

1989; Nicolson 1992) asked parents to rate their perceptions of

their child’s preoperative hunger. Details can be referred to in Ta-

ble 33 Volume of Fluid versus Standard Fast - Hunger.

Only two trials noted a statistically significant difference between

children’s hunger as rated by the children (Splinter 1989) or by

their parents (Splinter 1989; Nicolson 1992). In both cases the

children permitted a low or unlimited volume of fluids preoper-

atively reported less hunger than those children who fasted. No

differences in the reports of the children’ hunger was noted in the

remaining trials.

• Behaviour

Four trials asked parents to record their children’s preoperative be-

haviour using a VAS. Comparisons were made between those chil-

dren who followed a standard fast and those who were permitted

the preoperative intake of a low (Gombar 1997), high (Splinter

1990a; Splinter 1990b) or unlimited volume of fluids (Schreiner

1990). In three of the four trials parents of children permitted flu-

ids described their children as significantly less irritable and upset

than the parents of children who fasted in the standard manner.

Only Splinter 1990b found no difference between the two groups.

See Table 34 Volume of Fluid versus Standard Fast - Behaviour for

details.

• Comfort

Two trials compared the unlimited intake of clear fluids to a stan-

dard fasting regimen by asking parents to rate their children’s pre-

operative comfort on a VAS (Nicolson 1992; Schreiner 1990).

In both cases the parents of children permitted a drink described

their children as more comfortable than did the parents of children

who continued to fast preoperatively. Schreiner 1990 also asked

18 parents how the experimental fasting regimen had been experi-

enced by the children compared with previous experiences. Most

parents (14/18) said the unlimited intake of clear fluids preopera-

tively had improved the preoperative experience for their children.

Four parents had no opinion.

• Vomiting

The incidence of vomiting during the preoperative period was

available in relation to six trials as either published or unpublished

information. Trials compared groups of children who followed

either a standard fast or were permitted a low (Goresky 1992a;

Goresky 1992b), high (Aun 1990; Maekawa 1993a; Maekawa

1993b) or unlimited volumes (Schreiner 1990) of preoperative

fluids. No between group differences were observed in four of the

trials (Aun 1990; Maekawa 1993a; Maekawa 1993b; Schreiner

1990). Some reports of vomiting observed on introduction of the

intervention were made in Goresky 1992a and Goresky 1992b (n

= 8) but it is unclear to which group these individuals belonged.

The vomiting appears to have occurred in response to the taste

of the intervention and marker dye. Details can be referred to in

Table 36 Volume of Fluid versus Standard Fast - Vomiting.

Comparison 08: Volume of intake - volume 1 versus volume 2



Only one trial (Splinter 1990c) directly compared two volumes of

fluid intake. The outcome measures of (01) aspiration/regurgita-

tion, (02) volume of gastric contents, (03) pH of gastric contents

and (04) the secondary outcome measures were considered and are

presented below in turn. Splinter 1990c did not use any marker

dye measures nor were children’s ratings of comfort, nausea or

vomiting recorded.

Outcome 01: Aspiration/RegurgitationSplinter 1990c directly compared the preoperative intake of 6

ml/kg (n = 30) and 10 ml/kg (n = 32) of apple juice by children

up to 2.5 hours preoperatively. No aspiration or regurgitation was

observed. See Table 30 Volume of Intake - Aspiration/Regurgita-

tion for details.

Outcome 02: Gastric Contents - VolumeSplinter 1990c compared the intake of the two different volumes

of apple juice by measuring the volume of gastric contents. There

was no indication of a difference between 6 ml/kg (n = 30) and

10 ml/kg (n = 32) of apple juice (WMD -0.05 ml/kg, 95% CI

-0.44 to 0.34) and the results can be referred to in Comparison:

08 Volume of Intake - Volume 1 [V1] versus Volume 2 [V2];

Outcome 02 Gastric Contents - Volume. Particles were observed

in the gastric aspirate of one child permitted 6 ml/kg and four

children permitted 10 ml/kg of apple juice. All five were noted to

have gastric volumes in excess of 1 ml/kg.

Outcome 03: Gastric Contents - pHThe intake of 6 ml/kg and 10 ml/kg of apple juice preoperatively

was also compared by measuring the pH of children’s gastric con-

tents (Splinter 1990c). There was no evidence of a difference be-

tween the children who had the lower volume of apple juice (n

= 30) and those who had the higher volume (n = 32) (WMD

-0.10, 95% CI -0.45 to 0.25). These results can be referred to in

Comparison: 08 Volume of Intake - Volume 1 versus Volume 2;

Outcome 03 Gastric Contents - pH.

Secondary OutcomesSplinter 1990c asked the children participating to report their

thirst and hunger and their parents were asked to rate their chil-

dren’s behaviour over the preoperative period on a VAS. Two chil-

dren aged less than five years were unable to complete the VAS.

There was no difference in reports of thirst and hunger between

children permitted 6 ml/kg and 10 ml/kg of apple juice during

the preoperative period, nor was there any difference in parents’

description of how irritable the children were over the preopera-

tive period. For details see Table 37 Volume 1 versus Volume 2 -

Thirst; Table 38 Volume 1 versus Volume 2 -Hunger and Table

39 Volume 1 versus Volume 2 - Behaviour.

For summary of Volume of Intake Results - see end of results

section.

D. Subgroups of ’high-risk’ patient populations

Patient groups with delayed gastric emptying are considered to

be at an increased risk of regurgitation/aspiration/related morbid-

ity during anaesthesia. Conservative approaches to preoperative

fasting are generally employed with these patient groups which

include those with systemic disease/disorders (for example dia-

betes) and the obese. It is of note that this review failed to identify

any randomised controlled trial that specifically recruited children

from these ’high-risk’ groups.

Summary of results - A. Duration of fast

(where H2RA = H2-receptor antagonist; NSD = no statistically

significant difference)

Comparison 01: Short Fluid Fast versus Standard Fast

Outcome 01: Aspiration/RegurgitationNineteen trials; 1274 children; One incident - regurgitation and

aspiration possibly related to airway management.

Outcome 02: Gastric VolumeUp to 120 minutes: 7 trials (- H2RA); 509 children; WMD 0.03

ml/kg, 95% CI -0.03 to 0.10; NSD.

Up to 120 minutes: 1 trial (+ H2RA); 33 children; WMD

0.01ml/kg 95% CI -0.12 to 0.14; NSD.

Up to 150 minutes: 3 trials; 173 children; WMD 0.07 ml/kg 95%

CI -0.25 to 0.39; NSD.

Up to 180 minutes: 8 trials; 530 children; WMD -0.12 ml/kg

95% CI -0.22 to -0.03; Favours Fluid Intake (p = 0.01).

Up to 240 minutes: 3 trials; 125 children; WMD 0.03 ml/kg 95%

CI -0.10 to 0.17; NSD.

Outcome 03: Gastric pHUp to 120 minutes: 8 trials (- H2RA); 484 children; WMD 0.04

95% CI -0.01 to 0.09; NSD.

Up to 120 minutes: 2 trials (+ H2RA); 129 children; WMD 0.53

95% CI -0.20 to 1.26; NSD.

Up to 150 minutes: 3 trials; 173 children; WMD 0.19 95% CI

-0.11 to 0.49; NSD.

Up to 180 minutes: 8 trials; 465 children; WMD 0.32 95% CI

-0.14 to 0.78; NSD.

Up to 240 minutes: 2 trials; 76 children; WMD -0.02 95% CI

-0.23 to 0.18; NSD.

Outcome 04: Gastric Contents measured by Marker DyePhenol RedUp to 120 minutes; 1 trial; (- H2RA); 32 children; NSD.

Up to 120 minutes; 1 trial; (+ H2RA); 33 children; NSD.

Up to 180 minutes; 1 trial; 44 children; WMD -3.10 ml 95% CI

-6.66 to 0.46; NSD.

BromosulphthaleinUp to 120 minutes; 2 trials; (- and + H2RA); 240 children; No

evidence of a difference (combined groups).

Secondary OutcomesTwelve trials. Where differences occurred, fasted children (or their

parents) rated thirst and hunger as worse than those who were

given fluids. Similarly, parents or children were asked to report

behaviour and comfort and those children who were permitted



fluids were described as less irritable and more comfortable than

those that fasted in the standard manner. Eight children across two

comparisons were reported as vomiting gagging or spitting out an

intervention but it is unclear to which intervention they belonged.

Comparison 02: Short Solid and Fluid Fast versus Standard

Fast

Outcome 01: Aspiration/RegurgitationTwo trials; 86 children; No aspiration/regurgitation.

Outcome 02: Gastric VolumeSolids and Fluids up to 120 minutes: 1 trial; 52 children; WMD

0.25 ml/kg 95% CI 0.07 to 0.43; Favours Standard Fast (p =

0.006).

Solids and Fluids up to 240 minutes: 1 trial; 34 children; WMD

0.09 ml/kg 95% CI -0.12 to 0.30; NSD.

Outcome 03: Gastric pHSolids and Fluids up to 120 minutes: 1 trial; 43 children; WMD

0.35 95% CI -0.08 to 0.78; NSD.

Solids and Fluids up to 240 minutes: 1 trial; 24 children; WMD

0.11 95% CI -0.13 to 0.35; NSD.

Outcome 04: Gastric Volume measured by Marker DyeNot addressed.

Secondary OutcomesNot addressed.

Comparison 03: Short Solid and Fluid Fast versus Short Fluid

Fast


Outcome 02: Gastric VolumeUp to 120 minutes: 1 trial; 67 children; WMD 0.09 ml/kg 95%

CI -0.08 to 0.26; NSD.

Up to 240 minutes: 1 trial; 29 children; WMD 0.04 ml/kg 95%

CI -0.18 to 0.26; NSD.

Up to 330 minutes: 1 trial; 20 children; WMD 0.12 ml/kg 95%

CI -0.30 to 0.54; NSD.

Outcome 03: Gastric pHUp to 120 minutes: 1 trial; 60 children; WMD 0.06 95% CI -0.57

to 0.69; NSD.

Up to 240 minutes: 1 trial; 22 children; WMD 0.18 95% CI -0.13

to 0.49; NSD.

Up to 330 minutes: 1 trial; 20 children; WMD 0.46 95% CI -0.03

to 0.95; NSD, (p = 0.07).


Secondary OutcomesOne trial. Children permitted solids and fluids reported less

hunger that those permitted fluids alone. Thirst, behaviour, com-

fort, nausea, vomiting were not addressed.

Comparison 04: Short Fluid Fast 1 versus Short Fluid Fast 2

Outcome 01: Aspiration/RegurgitationFour trials; 365 children; No aspiration/regurgitation.

Outcome 02: Gastric VolumeUp to 120 versus 150 minutes: 1 trial; 100 children; WMD 0.06

ml/kg 95% CI -0.05 to 0.17; NSD.

Up to 120 versus 180 minutes: 2 trials; 248 children; WMD 0.04

ml/kg 95% CI -0.08 to 0.15; NSD.


ml/kg 95% CI -0.13 to 0.13; NSD.

Up to 150 versus 180 minutes: 2 trials; 180 children; WMD -0.04

ml/kg 95% CI -0.16 to 0.09; NSD.

Outcome 03: Gastric pHUp to 120 versus 150 minutes: 1 trial; 100 children; WMD 0.10

95% CI -0.41 to 0.61; NSD.


95% CI -0.36 to 0.61; NSD.


95% CI -0.33 to 0.60; NSD.


95% CI -0.12 to 0.50; NSD.


Secondary OutcomesTwo trials. No difference in parents’ ratings of children’s hunger

or behaviour across groups. No vomiting observed.

Summary of results - B. Type of permitted intake

Comparison 05: Type of Intake v Standard Fast

Water versus Standard Fast

Outcome 01: Aspiration/RegurgitationOne trial; 50 children; No aspiration/regurgitation.

Outcome 02: Gastric VolumeOne trial; 50 children; WMD -0.04 ml/kg 95% CI -0.16 to 0.08;

NSD.

Outcome 03: Gastric pHOne trial; 49 children; WMD 0.27 95% CI -0.12 to 0.66; NSD.


Secondary OutcomesOne trial. Children given water preoperatively reported less thirst

than the fasted group. Parents rated the children permitted water

as less irritable than those children who fasted.

Other Clear Fluids versus Standard Fast

Outcome 01: Aspiration/RegurgitationThree trials; 333 children; No aspiration/regurgitation.

Outcome 02: Gastric Volume



Five trials; 541 children; WMD -0.02 ml/kg 95% CI -0.09 to

0.05; NSD.

Outcome 03: Gastric pHFour trials; 455 children; WMD 0.09 95% CI -0.03 to 0.21; NSD.


Secondary OutcomesFour trials. Children given clear fluids preoperatively reported less

thirst than the fasted groups. Children permitted clear fluids were

rated by parents as less hungry, less irritable and more comfortable

than the children who fasted. There was no difference in children’s

reports of hunger. No vomiting was noted.

Fruit Juice versus Standard Fast

Outcome 01: Aspiration/RegurgitationSeven trials; 518 children; One incident - regurgitation and aspi-

ration in group permitted fruit juice.

Outcome 02: Gastric VolumeSeven trials (- H2RA); 394 children; WMD 0.02 ml/kg 95% CI

-0.08 to 0.11; NSD.

One trial (+ H2RA); 33 children; WMD 0.01 ml/kg 95% CI -0.11

to 0.13; NSD.

Outcome 03: Gastric pHEight trials (- H2RA); 455 children; WMD 0.04 95% CI -0.01

to 0.10; NSD.

Two trials (+ H2RA); 129 children; WMD 0.53 95% CI -0.19 to

1.26; NSD.

Outcome 04: Gastric Volume measured by Marker DyePhenol RedOne trial; 44 children; WMD -3.10 ml 95% CI -6.66 to 0.46;

NSD.

Secondary OutcomesSeven trials. Where differences were noted, children permitted

apple juice preoperatively described less thirst and hunger than the

fasted group. Parents reported the children permitted apple juice

were less irritable than those that fasted. Some vomiting noted (n

= or < 8) but exact number unclear as number included children

who gagged or spat out intervention.

Milk versus Standard Fast


Outcome 02: Gastric VolumeOne trial; 64 children; WMD 0.08 ml/kg 95% CI -0.29 to 0.45;

NSD.

Outcome 03: Gastric pHOne trial; 27 children; WMD -0.01 95% CI -1.82 to 1.80; NSD.

Outcome 04: Gastric Volume measured by Marker Dye

Not addressed


Dextrose Solution versus Standard Fast


Outcome 02: Gastric VolumeThree trials; 110 children; WMD -0.14 ml/kg 95% CI -0.43 to

0.15; NSD.

Outcome 03: Gastric pHTwo trials; 65 children; WMD -0.51 95% CI -2.21 to 1.19; NSD.

Outcome 04: Gastric Volume measured by Marker DyeNot addressed


Other Fluids versus Standard Fast

Outcome 01: Aspiration/RegurgitationFour trials; 193 children; No aspiration/regurgitation.

Outcome 02: Gastric VolumeFour trials; 156 children; WMD -0.13 ml/kg 95% CI -0.41 to

0.16; NSD.

Outcome 03: Gastric pHFour trials; 121 children; WMD 0.34 95% CI -0.62 to 1.31; NSD.


Secondary OutcomesOne trial. No vomiting noted.

Comparison 06: Fluid 1 versus Fluid 2

Dextrose versus Polyjoule



NSD.



Secondary OutcomesNot addressed

Dextrose versus Cows’ Milk

Outcome 01: Aspiration/Regurgitation



One trial; 60 children; No aspiration/regurgitation.

Outcome 02: Gastric VolumeOne trial; 60 children; WMD -0.44 ml/kg 95% CI -0.75 to -0.13;

Favours Dextrose (p = 0.005).

Outcome 03: Gastric pHOne trial; 29 children; WMD -1.74 95% CI -3.09 to -0.39;

Favours Cows’ milk (p = 0.01).



Polyjoule versus Cows’ Milk


Outcome 02: Gastric VolumeOne trial; 61 children; WMD -0.47 ml/kg 95% CI -0.78 to -0.16;

Favours Polyjoule (p = 0.003).




Summary of results - C. Volume of permitted intake

Comparison 07: Volume of Fluid versus Standard Fast

Low Volume Fluid Intake versus Standard Fast

Outcome 01: Aspiration/RegurgitationFive trials; 410 children; one incident - regurgitation and aspira-

tion.

Outcome 02: Gastric VolumeFour trials (- H2RA); 202 children; WMD -0.12 ml/kg 95% CI

-0.29 to 0.05; NSD.

One trial (+ H2RA); 33 children; WMD 0.01 ml/kg 95% CI -0.11

to 0.13; NSD.

Outcome 03: Gastric pHFive trials (- H2RA); 290 children; WMD 0.42 95% CI -0.19 to

1.04; NSD.

Two trials(+ H2RA); 129 children; WMD 0.53 95% CI -0.19 to

1.26; NSD.


Secondary OutcomesFour trials. Where there was a difference, children given a low

volume of fluids preoperatively (or their parents) reported less

thirst and hunger than those that fasted. Children who fasted were

reported by parents as more irritable than those in the low volume

fluid group. Some reports of vomiting made (two related trials)

but report includes children who gagged or spat out intervention

(n = 8).

High Volume Fluid Intake versus Standard Fast

Outcome 01: Aspiration/RegurgitationTen trials; 431 children; No aspiration/regurgitation.

Outcome 02: Gastric VolumeEleven trials; 495 children; WMD 0.04 ml/kg 95% CI -0.05 to

0.13; NSD.

Outcome 03: Gastric pHTen trials; 370 children; WMD 0.04 95% CI -0.02 to 0.09; NSD.


Secondary OutcomesFive trials. Where a difference was noted, children permitted a

high volume of fluids preoperatively were less thirsty and irritable

than those in the fasted group. There was no difference between

the children’s hunger or the incidence of vomiting.

Unlimited Fluid Intake versus Standard Fast

Outcome 01: Aspiration/RegurgitationThree trials; 333 children; No aspiration/regurgitation.

Outcome 02: Gastric Volume5 trials; 541 children; WMD -0.02 ml/kg 95% CI -0.09 to 0.05;

NSD.

Outcome 03: Gastric pH5 trials; 455 children; WMD 0.09 95% CI -0.03 to 0.21; NSD.


Secondary OutcomesThree trials. Where a difference was noted, children permitted

unlimited volumes of fluid preoperatively were reported to be less

thirsty and hungry than the children who were fasted. Parents also

rated them as less irritable but more comfortable than those that

fasted. There was no between group difference in the incidence of

vomiting.

Comparison 08: Volume 1 versus Volume 2



NSD.




Outcome 04: Gastric Content measured by Marker DyeNot addressed

Secondary OutcomesOne trial. No difference in the two groups’ description of preop-

erative thirst or hunger. No difference in behaviour.

’High risk’ populations:

No children considered to be at an increased risk of regurgitation

and aspiration during anaesthesia were specifically addressed by

any trial within this review.

Sensitivity analysis

As planned at protocol stage, we conducted a sensitivity analysis

to evaluate the impact of including trials known to have employed

inadequate methods of randomisation. These methods included

randomisation by alternate cases (Kushikata 1996), operation list

(Meakin 1985a; Meakin 1985b; Meakin 1985c; Meakin 1985d;

Meakin 1985e; Meakin 1985f) and day of the week (Welborn

1993). The original results and the results excluding the above

trials can be found in Table 40. Only one result was noted to

alter. On pooling the remaining data within Comparison: 05 Type

of Intake - Fluid versus Standard Fast, 07 Other Fluids versus

Standard Fast the children administered Polyjoule or an isosmolar

solution of electrolytes solution were found to have significantly

lower gastric volume than those children who fasted (WMD -0.38

ml/kg, 95% CI -0.58 to -0.19 p = < 0.0001). This comparison

did not demonstrate a significant difference when all trials are

included.

The only available data in relation to the preoperative intake of

solids was provided by the Meakin 1985 and Kushikata 1996 trials

(see Comparison: 02 Duration - Short Solid Fluid Fast versus

Standard Fast and 03 Duration - Short Solid Fluid Fast versus Short

Fluid Fast) and so a sensitivity analysis was unnecessary for these

comparisons. Similarly, for Comparison Duration - Short Fluid

Fast versus Standard Fast 05 Fluids (up to 240 minutes preop)

only one trial Maekawa 1993b remains when Meakin 1985e is

excluded and so a sensitivity analysis was not conducted for this

comparison.

D I S C U S S I O N

In this review we aimed to systematically identify, appraise and

synthesise the reliable evidence from valid research in relation to

preoperative fasting for children. We appraised this evidence in re-

lation to children’s safety and comfort, directly or indirectly, using

a variety of outcome measures. The complexity of the preopera-

tive fasting intervention was addressed by looking at the evidence

relating to the three main parameters of a fasting regimen i.e. the

duration of fast and the type and volume of intake permitted dur-

ing a period of restricted intake. We also searched for evidence in

relation to specific ’high-risk’ patient groups. These complexities

were not unexpected and had already been addressed by the related

adult based review (Brady 2004).

We encountered some additional complexities, including the need

to consider specific age groups (e.g. neonates, infants, children).

Many trials were based on children whose ages spanned these sub-

group bandings and while the resulting evidence was of relevance

it was not specific to these groups. This was surprising given the

great clinical awareness of the different physiological and psycho-

logical needs of these subgroups of children.

We identified a need to define a ’traditional’ or ’standard’ fasting

regimen. The traditional approach to the care of children preoper-

atively often indicated a more lenient approach to fasting (which

also accounted for the age of the child) than the ’nil-by-mouth-

from-midnight’ fast observed in adult practice. As a result, the

review classified a ’typical’ traditional standard fast of NPO for 4

hours for infants 1-12 months, 6 hours for children 12 months-5

years and 8 hours for children over the age of 5 years.

The data in relation to the primary outcome measure of aspiration

and regurgitation (and associated morbidity) was sparse. Of 1208

children in the trials that reported this primary outcome only one

incident of aspiration and regurgitation was reported and this (ac-

cording to the trialists) appeared to have been related to airway

management rather than as a result of the intervention. Given the

rarity of the incidence of regurgitation and aspiration we must be

cautious in making any firm judgements based on this evidence.

While some trialists reported on the incidence of aspiration and

regurgitation as an outcome (or made this information available to

the authors), most relied on surrogate measures of risk - children’s

gastric volume and pH during surgery. Most surrogate outcome

measures are known to be poorly validated (for example DeMets

2002), and the validity of the link between regurgitation, aspira-

tion, associated morbidity and mortality and the surrogate mea-

sures of gastric volume and pH is no exception. Thus we can only

make some tentative extrapolations about the risk of aspiration on

the basis of the evidence from these surrogate outcomes. We can

however be more confident about the effect of the various fasting

regimens on children’s gastric pH and volume.

To permit inclusion within the review of trials that did not re-

port (and the data were unavailable) mean and SD data, we cal-

culated pseudo-means and pseudo-standard deviations (Arnold

1992; O’Rourke 2002) . The use of actual means and SDs would,

of course, be preferential and we would encourage researchers and

editors to report (or make available) such data for meta-analysis

purposes - in addition to the median and ranges that better de-

scribe the study population characteristics. In fact, it would be

preferable to report at least the mean, SD, median, minimum,

maximum, 25th and 75th percentile for each group reported on

and ideal to list the sorted outcome values for each group or the

mean and SD and every nth outcome value as space permits.



After collecting and presenting the evidence in relation to the in-

take of fluids during a period of restricted intake there is no evi-

dence to indicate that children permitted fluids up to 120 minutes

preoperatively experience higher gastric volumes or lower gastric

pH values than those children who fasted. Interestingly, the confi-

dence intervals observed also suggest there is little possibility that

a clinically important difference exists in relation to the children’s

gastric pH and volume. We found similar results in our review

based on adults (Brady 2004). Children permitted fluids up to 180

minutes preoperatively actually had a lower mean gastric volume

(WMD 0.12 ml/kg) than those who had experienced a prolonged

fast, though this difference is not considered to be clinically signif-

icant. Where differences were noted, the children permitted fluids

were also noted to be less thirsty and hungry and better behaved

and more comfortable than the children who fasted. These find-

ings are supported by the trials that made a direct comparison be-

tween the intake of fluids at two different time points. When com-

pared with children permitted fluids at 150, 180 and 240 min-

utes preoperatively there was no difference in the groups’ gastric

volume or pH nor in their descriptions of hunger, behaviour or

vomiting.

The outcome measures thirst, hunger and comfort were prob-

lematic. Not only are such outcomes based on subjective ratings

transferred to a VAS, but the ratings for some children were made

by proxy, with parents reporting on their child’s thirst, hunger or

other aspects of their child’s preoperative experience. In addition,

the difficulties of attempting to blind the raters as to whether they

(or their child) were given something to drink or eat have already

been mentioned. In some cases very young children (less than 5

years) were unable to complete a VAS and so their reports of the

experience were not included within the results.

The evidence in relation to the intake of solid food was less defini-

tive with only a handful of small pioneering trials conducted that

employed alternation (now known to be inadequate) methods of

randomisation. The type of solid intake varied between plain bis-

cuits (Meakin 1985) and rice porridge (Kushikata 1996), as did

the timing of the solid intake which ranged from up to 120 and

330 minutes preoperatively. No aspiration or regurgitation was re-

ported, although there was some indication (Meakin 1985b) that

the children permitted biscuits and a drink 120 minutes preop-

eratively had a higher mean gastric volume than the fasted group

(WMD 0.25 ml/kg). Particles of ingested food were observed in

the gastric aspirate of a quarter of children. At present, the avail-

able evidence does not support a shift in practice from the current

established guidelines which permit children solid food up to 6 (or

8 hours) preoperatively until additional evidence can be reviewed.

Additional large, high quality studies are required to extend the

evidence in this area.

We also evaluated the available evidence relating to the type of

fluid intake within the review. The range of fluids included water,

clear fluid, dextrose solution (all of which could be classed as clear

fluids) milk and other fluids (for example orange squash). The tri-

als that investigated the preoperative intake of clear fluids demon-

strated narrow confidence intervals and thus provide little support

for the existence of a clinically important difference between the

gastric volume or pH of children permitted clear fluids and those

that fasted. Where there was a difference between the groups, the

children given a drink were less thirsty and hungry, better behaved

and more comfortable than the children who fasted. This finding

again supports the finding of the adult review (Brady 2002) and

current preoperative fasting recommendations that indicate clear

fluids can be permitted up to two hours preoperatively. As for most

of the comparisons in this review, however, the trials were based

on fewer than 100 children and additional evidence from larger

studies would be welcome.

Other fluids administered preoperatively included orange juice,

apple juice and orange squash. Some fruit juice interventions also

included an H2-receptor antagonist co-intervention, so evalua-

tions of the type of fluid intake within the review were often the

result of a single trial conducted on a small number of children.

Where direct comparisons of two different types of intervention

were possible, some significant between group differences were

noted and indicate further avenues for targeting through more

rigorous investigations. For example, one small trial suggests that

children who drank dextrose or Polyjoule had a lower volume of

gastric contents than children that were given cows’ milk. Con-

versely, the children who drank dextrose had more acidic gastric

contents that those that drank cows’ milk. Additional investiga-

tion of these issues is warranted.

The evidence in relation to the preoperative intake of milk was sur-

prisingly lacking given the prominence this substance has amongst

the young children for nutritional intake. Only van der Walt 1989

(cows’ milk) and Cook-Sather 2003 (formula milk) addressed the

intake of milk in their investigations. There is insufficient evi-

dence on the basis of these two small trials to guide clinical prac-

tice though some additional non-randomised studies can also be

referred to (e.g. Litman 1994; Sethi 1999; van der Walt 1990).

For clinical purposes, guidance in relation to the intake of milk

by children during the preoperative period should be sought from

the available professional guidelines (e.g. ASA 1999; RCN). This

is a complex issue and will require detailed study given the variety

of milk types available to children but this should not dissuade

researchers from addressing the need for high quality evidence in

this area.

The volume of the fluid intake permitted preoperatively did not

did not appear to have an impact on children’s gastric volume or

pH when compared with a standard fast. The majority of trials

permitted children to drink what was classified for the purposes of

this review as a high volume [over 5 ml/kg] while others permitted

children an unlimited volume of fluid intake. There were some

reports of children refusing to drink the intervention or declin-

ing to drink the prescribed volume in full (for example Sandhar



1989a). Across the trials that addressed the low, high and unlim-

ited intake of fluid there was no significant difference in relation to

the intra-operative gastric volume or pH contents from those who

drank and those who fasted. Narrow confidence intervals amongst

the trials that addressed the intake of unlimited fluids were noted

in relation to gastric volume and pH supporting the assertion it

is unlikely that a clinically important difference exists. The one

small, high quality trial that directly compared two different vol-

umes of intake (6 ml/kg and 10 ml/kg of apple juice) did not find

a significant difference in volume of gastric contents or on any of

the secondary outcome measures. The results of the parallel re-

view based on adults (Brady 2004) also suggested the volume of

intake was unlikely to be of significance. Current national clinical

guidelines have taken a pragmatic approach and omit mention of

specific volumes in relation to preoperative fluid intake (AAGBI

2001; ASA 1999; NHSQIS 2003).

As noted in the Methodological Quality section most trials within

this review employed some of the procedures that minimise the

possibility of bias. For example detailed listing of inclusion and

exclusion criteria and using appropriate methods to generating the

randomisation sequence in a non-biased manner. However, as has

been previously discussed (Brady 2004; Søreide 1995) additional

steps towards methodological quality could have been taken in

many preoperative fasting trials by ensuring concealment of the

children’s

allocation to the control and intervention groups. Awareness of

the importance allocation concealment in preventing bias in a ran-

domised trial is a relatively new development (Schultz 2001) and

so it is not surprising that only some of the more recently con-

ducted trials adequately utilised this precaution. This is something

that future research in this area should strive to incorporate within

the study design.

This review failed to identify any RCT that specifically recruited

children considered to be at an increased risk of regurgitation

and aspiration. In most cases children were recruited from a very

specific surgical population group i.e. healthy, ASA I-II children

undergoing elective surgery. The findings are therefore applica-

ble only to those patient populations and do not extend to many

groups considered to be at high risk of regurgitation/aspiration, for

example obese children or emergency cases. The global rising epi-

demic of obesity amongst children has been widely acknowledged

(IASO 2004; WHO 2003) together with the realisation of the

concomitant problems this group of children will experience (for

example diabetes, hypertension). In England obesity has tripled in

the last twenty years and if childhood obesity continues unchecked

by 2020 half of all children will be obese (Health Comm 2004).

There is an urgent need to establish high quality evidence that

relates specifically to the preoperative intake and fasting needs of

this group. The only relevant evidence available at the moment

is based on a single high quality trial within which obese adults

permitted 300 ml of clear fluids two hours preoperatively had a

statistically and clinically significant higher mean gastric volume

than the group that fasted from midnight (Maltby Ptyka 2004).

Only one trial included within the review recruited children who

were classified as ASA III-IV undergoing cardiac surgical proce-

dures. This ASA rating refers to children who have a severe sys-

temic disease that is (at ASA IV) a constant threat to life. Only

two children within this trial were classified as ASA IV. As the

ASA classification system is an indicator of surgical risk and not

as an indicator for risk of regurgitation and aspiration, a decision

was made to include this trial within the main body of the re-

view. The results of this high quality trial (n = 91) taken in iso-

lation found no difference between the children permitted intake

of unlimited clear fluids up to 120 minutes preoperatively and

the control group that were permitted clear fluids. The children

who followed the less conservative fast were also described as less

thirsty, less hungry and more comfortable than the children who

fasted. Other ’high-risk’ preoperative groups also require closer

consideration including children undergoing urgent and emer-

gency surgery (NCEPOD 2002) or those with particular preop-

erative nutritional needs such as those with cancer (for example

Sala 2004). For other groups, for example children with gastroin-

testinal disease or disorders, there appears to be some debate as

to whether they are actually at increased risk of regurgitation and

aspiration (for example Schwartz et al 1998).

A U T H O R S ’ C O N C L U S I O N S

Implications for practice

Multidisciplinary teams responsible for the care of surgical patients

should be aware of the evidence in relation to preoperative fasting,

the relevant clinical guidelines and local fasting policies. When-

ever possible such policies should be prepared with the involve-

ment of the whole team and presented in a simple and easy-to-

follow format. Compliance with preoperative fasting instructions

has always been crucial, but will become increasingly important

with the growth and promotion of day surgery for elective surgi-

cal procedures (Audit Commission). Staff will need to ensure that

children and their parents are educated on the benefits of more

relaxed fasting policies than the traditional fast.

Following this systematic review we can conclude there is evi-

dence that children at normal risk of regurgitation and aspiration,

given unlimited clear fluids up to two hours preoperatively are

not at a clinically significant risk of increased gastric volume and

pH than children who follow a standard fast. Similar conclusions

with regard to risk of aspiration/regurgitation can only be reached

with some cautious judgement. The risks of aspiration/regurgita-

tion were very low in this group of patients (either 1 or 0 out of

1208). Given this, the size of relative effect would be unacceptable

and the possibility that it may not be picked up via the surrogate

outcomes needs to be carefully considered. Children permitted a



drink during the preoperative period were found to be less thirsty,

less hungry, better behaved and more comfortable that those who

fasted. Clinical guidelines on the fasting of children before surgery

have preceded the publication of this review and urge clinicians to

permit the children to drink clear fluids up to two hours preop-

eratively (ASA 1999, Committee on Drugs) as do more generalist

guidelines (NNCG 1993).

It should be remembered however that this evidence (and the

recommendations made by available guidelines) only applies to

healthy children who are not considered to be at an increased risk

of aspiration/regurgitation during anaesthesia. There is a paucity

of evidence in relation to high-risk groups and so clear preopera-

tive fasting recommendations for these groups cannot be made at

this time. Conducting studies with some high-risk children (such

as children requiring emergency surgery) may never be ethically

possible. Additional sources of evidence and opinion including ob-

servational studies and best practice statements should be sought

when considering the preoperative fasting preparations for these

children.

Preoperative carers have an obligation to ensure that their pa-

tients are fully informed (Smith 2004) about the preoperative

fasting procedure and that this information is based on the cur-

rent evidence. Not only has a recent survey demonstrated that

information given to many patients in the UK falls short of this

(Markham 2003) but we also know that many sites still demand

that healthy patients remain nil-by-mouth-from-midnight. This

practice should no longer be tolerated.

Implications for research

Well designed, methodologically sound randomised controlled tri-

als are still required to further examine the intake of solid food

and some fluid types preoperatively. The paucity of evidence in

relation to the intake of milk is especially surprising given the re-

liance of younger children on this form of nutritional intake. Some

interesting developments in clinical practice indicate possible av-

enues of investigation with some children reportedly permitted

breast milk and formula up to two hours prior to surgery (Hofer

2001). Such fasting regimens are more lenient than the evidence

reviewed here would support and further investigation, reporting

and monitoring of this development should be a matter of priority.

Researchers should ensure that the numbers of children recruited

to such investigations are based on upon a priori sample size calcu-

lations and that adequate concealment of children’s allocation to

the trial groups should be incorporated whenever possible. Given

the tendency for the gastric volume and pH data to be skewed,

we would also encourage researchers to report mean and standard

deviation data thus permitting accurate representation of the data

within meta-analyses when required.

In clinical settings there is a clear awareness of the different pre-

operative fasting requirements for neonates, infants, children and

adolescents. This distinction is not reflected within the available

evidence and further investigation of these boundaries and gener-

ation of additional age-group specific evidence should be pursued.

In addition, many children considered to be at ’high-risk’ of regur-

gitation and aspiration (e.g. the growing population of obese chil-

dren or those with gastrointestinal disorders) have been specifically

excluded from the evidence presented here. High quality trials that

specifically target and recruit children from these groups would

provide much needed evidence in this area. It remains crucial that

the incidence of aspiration/regurgitation continues to be reported.

For the moment, the surrogate measures of risk i.e. intra-opera-

tive gastric content volume and pH should continue to be used,

though reliance on the ’critical values’ (Roberts 1974) should be

discouraged. The possibility of developing a clinically meaningful

composite surrogate outcome measure based on the two outcomes

of gastric volume and pH as a statistically more powerful indicator

of risk should be explored (DeMets 2002), though it is acknowl-

edged the development and use of such an outcome would not be

without its challenges (e.g. Cannon 1997, Freemantle 2003).

Despite the availability of research evidence, through reviews of

the literature and widely available guideline recommendations,

kick starting an evolution in fasting policies remains a difficult

task. Researchers should consider how best to communicate the

evidence from this review (and others) to the preoperative multi-

disciplinary team so that it has a positive impact on clinical prac-

tice during the preoperative period. Exploration of this issue will

no doubt raise issues such as the quality of patient (and parent)

preoperative education, the information communicated regarding

the preoperative fasting regimen and patient compliance.

N O T E S

Readers of this review should also refer to the companion review

published in the Cochrane Library:

Preoperative fasting for adults to prevent perioperative complica-

tions. Brady M, Kinn S, Stuart P.

P O T E N T I A L C O N F L I C T O F

I N T E R E S T

None known.

A C K N O W L E D G E M E N T S

The authors would like to thank

• The trial authors for their extensive contribution; the time they

took to respond to queries and the provision of additional details

whenever possible.

• Sally Bell-Syer, Nicky Cullum and Andrea Nelson from the

Cochrane Wounds Group for their assistance.



• Seokyung Hahn from the Cochrane Wounds Group for statis-

tical advice.

• Linda Scott, Debbie Cattermole, Sarah Hinks for assistance

with handsearching, re-running searches or second screening of

retrieved references.

• Namiko Ikeda, Audrey Morrison and Elizabeth Stirrat for trans-

lations.

• Cochrane Wounds Group referees (Anne Marie Bagnall, Adrian

Barbul, Michelle Briggs, Anne Humphreys) and the Cochrane

Anaesthesia Group Editor John Carlisle for their comments to

improve the review.

• The Cochrane Child Health Field Third Bursary Scheme for

support in completion of this Cochrane review in child health.

S O U R C E S O F S U P P O R T

External sources of support

• Chief Scientist Office, Scottish Executive UK

• Cochrane Child Health Field Bursary 2004 CANADA

Internal sources of support

• Nursing, Midwifery and Allied Health Professions Research

Unit UK

R E F E R E N C E S

References to studies included in this review

Aun 1990 {published and unpublished data}∗ Aun CS, Panesar NS. Paediatric glucose homeostasis during anaes-

thesia. British Journal of Anaesthesia 1990;64(4):413–8.

Cook-Sather 2003 {published and unpublished data}∗ Cook-Sather SD, Harris KA, Rosetta Chiavacci R, Gallagher PR,

Schreiner MS. A liberalized fasting guideline for formula-fed infants

does not increase average gastric fluid volume before elective surgery.

Pediatric Anesthesia 2003;96:965–9.

Crawford 1990a {published and unpublished data}∗ Crawford M, Lerman J, Christensen S, Farrow-Gillespie A. Effects

of Duration of Fasting on Gastric Fluid pH and Volume in Healthy

Children. Anesthesia & Analgesia 1990;71(4):400–3.

Farrow-Gillespie A, Christensen S, Lerman J. Effect of the Fasting

Interval on Gastric pH and Volume in Children. Anesthesia & Anal-

gesia. 1988;67:S59.

Crawford 1990b {published and unpublished data}∗ Crawford M, Lerman J, Christensen S, Farrow-Gillespie A. Effects


Children. Anesthesia & Analgesia 1990;71:400–3.



gesia 1988;67:S59.

Crawford 1990c {published and unpublished data}∗ Crawford M, Lerman J, Christensen S, Farrow-Gillespie A. Effects


Children. Anesthesia & Analgesia 1990;71:400–3.



gesia 1988;67:S59.

Gombar 1997 {published and unpublished data}∗ Gombar S, Dureja J, Kiran S, Gombar K, Chhabra B. The effect

of pre-operative intake of oral water and ranitidine on gastric fluid

volume and pH in children undergoing elective surgery. Journal of

the Indian Medical Association 1997;95(6):166–8.

Goresky 1992a {published data only}

Finely GA, Bissonnette B, Goresky GV, Klassen K, Lerman J, Mc-

Diarmid C, et al. The effect of oral ranitidine and preoperative oral

fluids on gastric fluid pH and volume in children. Canadian Journal

of Anaesthesia. 1989;36:S95.



∗ Goresky GV, Finley GA, Bissonnette B, Shaffer EA. Efficacy, Dura-

tion and Absorption of a Paediatric Oral Liquid Preparation of Ran-

itidine Hydrochloride. Canadian Journal of Anaesthesia 1992;39(8):

791–8.

Goresky 1992b {published data only}

Finely GA, Bissonnette B, Goresky GV, Klassen K, Lerman J, Mc-

Diarmid C, et al. The effect of oral ranitidine and preoperative oral

fluids on gastric fluid pH and volume in children. Canadian Journal

of Anaesthesia. 1989;36:S95.

∗ Goresky GV, Finley GA, Bissonnette B, Shaffer EA. Efficacy, Dura-

tion and Absorption of a Paediatric Oral Liquid Preparation of Ran-

itidine Hydrochloride. Canadian Journal of Anaesthesia 1992;39(8):

791–8.

Kushikata 1996 {published and unpublished data}∗ Kushikata T, Matsuki A, Murakawa T, Sato K. Possibility of rice

porridge for preoperative feeding in children [[Japanese]]. Masui -

Japanese Journal of Anesthesiology 1996;45(8):943–7.

Maekawa 1993a {published data only}∗ Maekawa N, Mikawa K, Yaku H, Nishina K, Obara H. Effects of

2-, 4- and 12-hour fasting intervals on preoperative gastric fluid pH

and volume, and plasma glucose and lipid homeostasis in children.

Acta Anaesthesiologica Scandinavica 1993;37(8):783–7.

Mikawa K, Maekawa N, Nishina K, Obara H. A short fasting interval

does not increase preoperative plasma atrial natriuretic polypeptide

concentrations in children. Acta Anaesthesiologica Scandinavica 1993;

37:713–4.

Maekawa 1993b {published data only}∗ Maekawa N, Mikawa K, Yaku H, Nishina K, Obara H. Effects of







37:713–4.

Maekawa 1993c {published data only}∗ Maekawa N, Mikawa K, Yaku H, Nishina K, Obara H. Effects of







37:713–4.

Meakin 1985a {published and unpublished data}

Meakin G, Dingwall AE, Addison GM. Effects of fasting and oral

premedication on the pH and volume of gastric aspirate in children.

British Journal of Anaesthesia 1987;59(6):678–82.

∗ Meakin G, Dingwall AE, Addison GM. Effects of Preoperative

Feeding on Gastric pH and Volume in Children. British Journal of

Anaesthesia. 1985;57:832–3P.

Meakin 1985b {published and unpublished data}




∗ Meakin G, Dingwall AE, Addison GM. Effects of Preoperative



Meakin 1985c {published and unpublished data}




∗ Meakin G, Dingwall AE, Addison GM. Effects of preoperative

feeding on gastric pH and volume in children. British Journal of


Meakin 1985d {published and unpublished data}∗ Meakin G, Dingwall AE, Addison GM. Effects of Preoperative



Meakin 1985e {published and unpublished data}∗ Meakin G, Dingwall AE, Addison GM. Effects of Preoperative



Meakin 1985f {published and unpublished data}∗ Meakin G, Dingwall AE, Addison GM. Effects of Preoperative



Miller 1990 {published and unpublished data}∗ Miller BR, Tharp JA, Issacs WB. Gastric Residual Volume in In-

fants and Children following a Three Hour Fast. Journal of Clinical

Anesthesia 1990;2:301–5.

Moyao-García 2001 {published and unpublished data}∗ Moyao-García D, Corrales-Fernández MA, Blanco-Rodríguez G,

Sánchez-Hernández E, Nava-Ocampo A. Benefits of oral administra-

tion of an electrolyte solution interrupting a prolonged preoperatory

fasting period in pediatric patients. Journal of Pediatric Surgery 2001;

36(3):457–9.

Nicolson 1992 {published and unpublished data}∗ Nicolson SC, Dorsey AT, Schreiner MS. Shortened Preanesthetic

Fasting Interval in Pediatric Cardiac Surgical Patients. Anesthesia &

Analgesia 1992;74:694–7.

Sandhar 1989a {published data only}∗ Sandhar BK, Goresky GV, Maltby JR, Shaffer EA. Effect of oral

liquids and ranitidine on gastric fluid volume and pH in children un-

dergoing outpatient surgery. Journal of Anesthesiology 1989;71:327–

30.

Sandhar BK, Goresky GV, Shaffer L, Strunin L. Pre-operative fasting

in children: how long is enough?. Canadian Journal of Anaesthesia.

1988;35:S141–2.

Sandhar BK, Maltby JR, Goresky G, Strunin, L. Preoperative fluids

and ranitidine in children. British Journal of Anaesthesia. 1988;60

(3):324P–5P.

Sandhar 1989b {published data only}∗ Sandhar BK, Goresky GV, Maltby JR, Shaffer EA. Effect of oral

liquids and ranitidine on gastric fluid volume and pH in children un-

dergoing outpatient surgery. Journal of Anesthesiology 1989;71:327–

30.



Sandhar BK, Goresky GV, Shaffer L, Strunin L. Pre-operative fasting

in children: how long is enough?. Canadian Journal of Anaesthesia.

1988;35:S141–2.

Sandhar BK, Maltby JR, Goresky G, Strunin L. Preoperative fluids

and ranitidine in children. British Journal of Anaesthesia. 1988;60

(3):324P–325P.

Sarti 1991 {published data only}∗ Sarti A, Calamandrei M, Messeri A, Busoni P. Preoperative Fasting

in Pediatrics [Il Digiuno Preoperatorio in Pediatria]. Minerva Aneste-

siologica 1991;57(11):1179–80.

Schreiner 1990 {published and unpublished data}∗ Schreiner MS, Triebwasser A, Keon TP. Ingestion of liquids com-

pared with preoperative fasting in pediatric outpatients. Anesthesiol-

ogy 1990;72:593–7.

Triebwasser A, Schreiner MS, Parness J, Keon TP. Effect of preop-

erative clear fluids gastric volume in children. Anesthesiology. 1989;

71:A1177.

Splinter 1989 {published and unpublished data}∗ Splinter WM, Stewart JA, Muir JG. The effect of preoperative apple

juice on gastric contents, thirst and hunger in children. Canadian

Journal of Anaesthesia 1989;36:55–8.

Splinter 1990a {published and unpublished data}∗ Splinter WM, Stewart JA, Muir JG. Large volumes of apple juice

preoperatively do not affect gastric pH and volume in children. Cana-

dian Journal of Anaesthesia 1990;37:36–9.

Splinter 1990b {published and unpublished data}∗ Splinter WM, Stewart JA, Muir JG. Large volumes of apple juice



Splinter 1990c {published and unpublished data}∗ Splinter WM, Stewart JA, Muir JG. Large volumes of apple juice



Splinter 1991 {published and unpublished data}∗ Splinter WM, Schaefer JD. Ingestion of clear fluids is safe for ado-

lescents up to 3 h before anaesthesia. British Journal of Anaesthesia

1991;66(1):48–52.

Splinter WM, Schneider ME, Schaefer JD. Unrestricted clear fluid

ingestion 3-hours before anesthesia is safe for adolescents. Anesthesia

& Analgesia. 1990;70:S387.

Splinter Schaefer 1a {published and unpublished data}

Splinter W, Schaefer JD, Zunder IH. A 2-hour clear fluid fast is safe

for children. Anesthesia & Analgesia. 1990;70:S386.

∗ Splinter WM, Schaefer JD. Unlimited clear fluid ingestion two

hours before surgery in children does not affect volume or pH of

stomach contents. Anaesthesia & Intensive Care 1990;18(4):522–6.

Splinter Schaefer 1b {published and unpublished data}

Splinter W, Schaefer JD, Zunder IH. A 2-hour clear fluid fast is safe

for children. Anesthesia & Analgesia. 1990;70:S386.

∗ Splinter WM, Schaefer JD. Unlimited clear fluid ingestion two

hours before surgery in children does not affect volume or pH of

stomach contents. Anaesthesia & Intensive Care 1990;18(4):522–6.

Splinter Schaefer 2 {published and unpublished data}∗ Splinter WM, Schaefer JD, Zunder IH. Clear fluids three hours

before surgery do not affect the gastric fluid contents of children.

Canadian Journal of Anaesthesia 1990;37(5):498–501.

Zunder IH, Splinter WM, Schaefer EA. Preoperative clear fluids do

not affect gastric pH and volume in children. Anesthesiology. 1989;

71:3A.

Splinter Schaefer 3a {published data only}∗ Splinter WM, Schaefer JD, Bonn GE. Unlimited clear fluid inges-

tion by infants up to 2 hours before surgery is safe. Canadian Journal

of Anaesthesia. 1990;37(4(ii)):S95.

Splinter Schaefer 3b {published data only}

Splinter WM, Schaefer JD, Bonn GE. Unlimited clear fluid ingestion

by infants up to 2 hours before surgery is safe. Canadian Journal of

Anaesthesia. 1990;37(4(ii)):S95.

Splinter Schaefer 3c {published data only}

Splinter WM, Schaefer JD, Bonn GE. Unlimited clear fluid ingestion

by infants up to 2 hours before surgery is safe. Canadian Journal of

Anaesthesia. 1990;37(4(ii)):S95.

van der Walt 1986a {published and unpublished data}

van der Walt JH, Carter J. Preoperative fasting in infancy. Anaesthesia

and Intensive Care. 1985;13(1):97.

∗ van der Walt JH, Carter JA. The effect of different pre-operative

feeding regimens on plasma glucose and gastric volume and pH in

infancy. Anaesthesia & Intensive Care 1986;14(4):352–9.

van der Walt 1986b {published and unpublished data}






van der Walt 1986c {published and unpublished data}






van der Walt 1986d {published and unpublished data}






van der Walt 1986e {published and unpublished data}






van der Walt 1986f {published and unpublished data}


and Intensive Care 1985;13(1):97.






Welborn 1993 {published data only}

Welborn L, Norden J, Hannallah R, Broadman L, Seiden N. Apple

juice ingestion two hours before surgery does not increase blood

glucose concentrations in pediatric patients. Canadian Journal of

Anaesthesia. 1992;39:A97.

∗ Welborn LG, Norden JM, Seiden N, Hannallah, RS, Patel, RI,

Broadman, L, et al. Effect of minimizing preoperative fasting on pe-

rioperative blood glucose homeostatsis in children. Paediatric Anaes-

thesia 1993;3:167–71.

References to studies excluded from this reviewBevan & Burn 1973

∗ Bevan JC, Burn MC. Acid-base and blood glucose levels of pae-

diatric cases at induction of anaesthesia: the effects of preoperative

starvation and feeding. British Journal of Anaesthesia. 1973;45(1):

115.

Bevan & Burn 1973b∗ Bevan JC, Burn MC. Acid-base changes and anaesthesia. The in-

fluence of pre-operative starvation and feeding in paediatric surgical

patients. Anaesthesia 1973;28(4):415–22.

Fry 1976∗ Fry ENS, Ibrahim AA. Hypoglycaemia in paediatric anaesthesia: the

influence of metoclopramide and oral maltose in paediatric surgical

patients. Anaesthesia 1976;31(4):552–4.

Graham 1979∗ Graham IF. Preoperative starvation and plasma glucose concentra-

tions in children undergoing outpatient anaesthesia. British Journal

of Anaesthesia 1979;51:161.

Hotta 1967∗ Hotta K. Effect of Pre-operative fasting and feeding on the acid

base equilibrium in new born infants and young children. Nippon

Shonika Gakkai Zasshi 1967;71(10):1288–300.

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MD. Sedation in children: adequacy of two-hour fasting. Journal of

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Jensen 1982∗ Jensen BH, Wernberg M, Andersen M. Preoperative Starvation and

Blood Glucose Concentrations in Children Undergoing Inpatient

and Outpatient Anaesthesia. British Journal of Anaesthesia 1982;54:

1071–4.

Litman 1994∗ Litman RS, Wu CL, Quinlivan JK. Gastric volume and pH in

infants fed clear liquids and breast milk prior to surgery. Anesthesia

& Analgesia 1994;79:482–5.

Morrice 1974∗ Morrice JJ, Taylor KM, Blair JI, Young DG. Preoperative plasma

glucose level. Archives of Disease in Childhood 1974;49:898–900.

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calories of preoperative oral intake on the glucose metabolic response

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glucose concentrations during anaesthesia in children. Effects of star-

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1984;56:375–9.

O’Flynn 1989∗ O’Flynn PE, Milford CA. Fasting in children for day case surgery.

Annals of the Royal College of Surgeons of England 1989;71(4):218–9.

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Metabolic consequences of different perioperative fluid therapies in

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170–5.

Schneider 1982∗ Schneider BM, Nahrwold ML. Fasting Plasma Glucose in Children.

Anesthesiology. 1982;57(Supp):A430.

Schurizek 1986∗ Schurizek BA, Rybro L, Boggild-Madsen NB, Juhl B. Gastric vol-

ume and pH in children for emergency surgery. Acta Anaesthesiologica

Scandinavica 1986;30(5):404–8.

Sethi 1999∗ Sethi AK, Chatterji C, Bhargava SK, Narang P, Tyagi A. Safe pre-

operative fasting times after milk or clear fluid in children. A pre-

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∗Indicates the major publication for the study

T A B L E S

Characteristics of included studies

Study Aun 1990

Methods RCT (drawing lots by person independent of trial)

Participants 20 children, 1-5 years, ASA I-II, inpatients, elective minor surgery (herniotomy, repair of hydrocele, circum-

cision) 8-9am.

Exclusions; ASA > II, difficult venous access, lack of parental consent.

Interventions 1. Standard Fast (n =10)

2. Dextrose solution (5%) [10ml/kg] 4 hrs preop (n =10)

Outcomes Gastric volume - post induction and intubation. Gastric pH - post induction and intubation.



Characteristics of included studies (Continued )

Plasma glucose concentrations; cortisol; growth hormone; glucagon; insulin concentration.

Notes Standard Fast = milk feed at midnight then NPO. Assessor blinding adequate. No gastric pH value for four

participants.

Premedication; trimeprazine (plus morphine & atropine 1 hr preop). IV fluids; none.

Allocation concealment A

Study Cook-Sather 2003

Methods RCT (computer generated sequence allocated by coded envelope)

Participants 97 children, 0-9 months at recruitment, ASA I-II, elective surgery requiring tracheal intubation (mainly cleft

lip and palate repair, hernia/hydrocele surgery, circumcisions. Exclusions: exclusively breast fed infants, those

with gastrointestinal disease that impede emptying or diminish motility or result in reflux.

Interventions 1. Clear fluids [unlimited] up to 2 hrs (n = 36)

2. Formula [unlimited] up to 4 hrs pre op (n = 31)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Irritability, Hunger, Parental satisfaction.

Notes No solids or cows milk from 8 hrs preop. Assessor blinding adequate. Premedication - atropine.

Protocol deviation 22 from group 1, 8 from group 2.


Study Crawford 1990a

Methods RCT (random numbers table)

Participants 100 children, 1-14 years, ASA I-II, inpatients, elective surgery.

Exclusions; gastrointestinal disease, obese (> 20% ideal body weight), those taking drugs known to affect

gastric fluid composition and emptying.

Interventions 1. Water [2 ml/kg] 2 hrs preop (n = ?)

2. Water [2 ml/kg] 6 hrs preop (n = ?)

Outcomes Gastric volume - post induction and intubation. Gastric pH - post induction and intubation. Marker dye

[Sulfobromophthalein sodium - BSP].

Notes Assessor blinding inadequate. Premedication- none. Not possible to extract group specific data from reports.

No gastric aspirate in at least one participant (abstract report).


Study Crawford 1990b















Study Crawford 1990c












Study Gombar 1997

Methods RCT (computer generated random numbers)

Participants 50 children, 2-12 years, ASA I-II, elective surgery (e.g. herniotomy, orchiopexy, tonsillectomy, myringoplasty,

hypospadias correction, circumcision, cystolithotomy, strabismus repair) (+ 25 children with pharmacological

co-intervention excluded from review). Exclusions; active gastrointestinal disease, taking medication affecting

gastric fluid volume, pH or motility.

Interventions 1. Standard Fast ( n = 25)

2. Water 5 ml/kg 3 hrs preop (n = 25)

(3. Water + Ranitidine n = 25 excluded from review)

Outcomes Gastric volume - post induction before surgical incision. Gastric pH - post induction before surgical incision.

Thirst, Behaviour.

Notes Standard Fast = NPO from midnight. Thirst/behaviour assessor blinded. No gastric pH value for one

participant. Premedication - none. IV fluids administered as required.

Allocation concealment B

Study Goresky 1992a

Methods RCT (method not reported)

Participants 120 children, 1-6 years, ASA I-II, elective minor surgery. Exclusions; known gastrointestinal disease, those

taking any medications including premedication (except benzodiazepines).

Interventions 1. Standard Fast + placebo (n = 60)

2. Apple juice [5ml/kg] + placebo 2hrs preop (n = 60)


[Sulfobromophthalein sodium - BSP]. Adverse events.

Notes Standard Fast = 5 ml of water. Assessors blinded to ranitidine/placebo. Premedication - only benzodiazepines.

Study supported by Glaxo Canada.

Allocation concealment D

Study Goresky 1992b


Participants 120 children, 1-6 years, ASA I-II, elective minor surgery. Exclusions; known gastrointestinal disease, those

taking any medications including premedication (except benzodiazepines).

Interventions 1. Standard Fast + Ranitidine [2 mg/kg] (n = 60)




2. Apple juice [5ml/kg] + Ranitidine [2mg/kg] 2hrs preop (n = 60)


[Sulfobromophthalein sodium - BSP]. Adverse events.

Notes Standard Fast = 5 ml of water. Assessors blinded to ranitidine/placebo. Premedication - only benzodiazepines.

Study supported by Glaxo Canada.


Study Kushikata 1996

Methods RCT (alternate cases)

Participants 20 children, 5-12 years, ’healthy’ inpatients, elective ENT surgery. Exclusions; not listed.

Interventions 1. Standard Fast (n = 10)

2. Rice porridge [55g rice + 245 ml water + some salt] 330 mins preop + clear fluids [< 200 ml] up to 5 hrs

preop (n = 10)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Hunger (?child).

Notes Standard Fast = Clear fluids [< 200 ml] up to 5 hrs preop. Assessor blinding unclear. Premedication (0.3mg/kg

of diazepam syrup). IV fluids - Lactic Ringer solution with 2% glucose 4ml/kg/hr.

Allocation concealment C

Study Maekawa 1993a


Participants 70 children, 1-14 years, ASA I, inpatients, elective surgery. Exclusions; those with metabolic disorder, gas-

trointestinal disease, obese (> 20% over ideal body weight), taking drugs affecting gastric fluid or emptying.


2. Apple Juice [10 ml/kg] 2 hrs preop (n = 35)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Vomiting. Plasma glucose, lipid homeostasis,

ANP concentration. Adverse events.

Notes Standard Fast = Apple juice [10 ml/kg] 12 hrs preop then NPO. Assessor blinding adequate. Gastric pH (n)

unclear. Premedication - none.


Study Maekawa 1993b








Notes Standard Fast = Apple juice [10 ml/kg] 12 hrs preop then NPO. Assessor blinding adequate. Gastric pH (n)

unclear. Premedication - none.


Study Maekawa 1993c







Interventions 1. Apple Juice [10 ml/kg] 2 hrs preop (n = 35).

2. Apple Juice [10 ml/kg] 4 hrs preop (n = 35).



Notes Assessor blinding adequate. Gastric pH (n) unclear. Premedication - none.


Study Meakin 1985a

Methods RCT (by operating list)

Participants 55 children, 1-16 years, ASA I-II, elective afternoon tonsillectomy or body wall surgery. Exclusions; those

with known gastrointestinal disorders, scheduled for intra-abdominal or major surgery.

(+103 with pharmacological co-intervention excluded from review).


2. Orange squash [10 ml/kg max 200 mls] 2 hrs preop (n = 35)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Adverse events.

Notes Standard Fast = NPO for at least 6 hrs. No gastric aspirate from 20 participants. Assessors adequately blinded

for pH and food particle evaluation. Premedication - none.


Study Meakin 1985b



with known gastrointestinal disorders, scheduled for intra-abdominal or major surgery.



2. Plain biscuits (x2) + Orange squash [10 ml/kg max 200 ml] 2 hrs preop (n = 32)


Notes Standard Fast = NPO for at least 6 hrs. No gastric aspirate from 19 participants. Assessors adequately blinded

for pH and food particle evaluation. Premedication - none.


Study Meakin 1985c



with known gastrointestinal

disorders, scheduled for intra-abdominal or major surgery.


Interventions 1. Orange squash [10 ml/kg max 200 mls] 2hrs preop (n = 35)

2. Plain biscuits (x2) + Orange squash [10 ml/kg max 200 mls] 2 hrs preop (n = 32)


Notes No gastric aspirate from 7 participants. Assessors adequately blinded for pH and food particle evaluation.

Premedication - none.





Study Meakin 1985d


Participants 49 children, 1-16 years, ASA I-II, elective surgery. Exclusions; those with known gastrointestinal disorders,

scheduled for intra-abdominal or major surgery.

(+67 reported in more detail in Meakin 1987a-c)

Interventions 1. Orange squash [10 ml/kg max 200 mls] 4 hrs preop (n = 15)


Outcomes Gastric volume - post induction. Gastric pH - post induction.

Notes Standard Fast = NPO for 6 hrs. Assessors adequately blinded for pH and food particle evaluation. Premedi-

cation - none.


Study Meakin 1985e






2. Orange squash [10 ml/kg max 200 mls] 4 hrs preop (n = 15)



cation - none.


Study Meakin 1985f









cation - none.


Study Miller 1990

Methods RCT (table of random numbers)

Participants 44 children, 1 month -5 years (greater than 44wks conceptual age), ASA I-II, elective surgery. Exclusions;

active cardiac, pulmonary, gastrointestinal disease.


2. Dextrose Solution (5%) [4 oz] 3 hrs preop (n = 19)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Marker dye [ phenolsulfonphthalein - phenol

red].




Notes Standard Fast = NPO for 10 hrs. 4US oz = 118 ml. Insufficient gastric aspirate to calculate volume and pH

for 23 participants. Assessor blinding unclear. Premedication - none.


Study Moyao-García 2001


Participants 40 children, 3-12 years, ASA I, elective surgery (ophthalmology, otorhinolaryngology, plastic surgery). Ex-

clusions: those taking drugs known to affect gastric motility or with any medical condition affecting gastric

or intestinal motility.


2. Isosmolar solution of electrolytes [4 ml/kg] 3 hrs preop (n = 20)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Blood glucose level.

Notes Standard Fast = no solids, milk or formula overnight for at least 8 hours preop. Assessor blinding adequate.

Premedication - none.


Study Nicolson 1992

Methods RCT (sealed envelopes)

Participants 100 children, ASA II-IV, (n II = 45; III = 44; IV = 2) inpatients, elective cardiac surgery. Exclusions; history

of gastrointestinal disease, taking medication known to affect gastric contents.


2. Clear fluids [unlimited] 2 hrs preop (n = 47)

Outcomes Gastric volume - post induction and intubation. Gastric pH - post induction and intubation. Thirst, Hunger,

Comfort.

Notes Standard Fast = after midnight clear fluids only [unlimited] up to 4 hrs (< 6 mths), 6 hrs (6 mths - 5 yrs)

or 8 hrs (> 5yrs) preop, NPO thereafter. Nine protocol deviations excluded. Assessor blinding adequate.

Premedication - < 6mth = atropine, 6-12mths = atropine + pentobarbital, > 1yr = meperidine.


Study Sandhar 1989a


Participants 44 children, 1-14 years, ASA I-II, outpatients, elective ENT, urology or minor general surgical procedures.

Exclusions; history of gastrointestinal disorder.

Interventions 1. Standard fast + placebo 2hrs preop (n = 19)

2. Orange juice [5ml/kg] + placebo 2hrs preop (n = 13)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Marker dye [ phenolsulfonphthalein - PSP].

Notes Placebo = glucose water [0.2 ml/kg]. Max juice intake for patients > 30 kg was 150 ml. Assessor blinding

unclear. Twelve protocol deviations (ingestion-surgery interval < 90mins, refused orange juice/drank water

instead, did not complete drink). No gastric pH value for three participants. pH values for an additional 7

participants not reported. Premedication - none.


Study Sandhar 1989b





Participants 44 children, 1-14 years, ASA I-II, outpatients, elective ENT, urology or minor general surgical procedures.

Exclusions: history of gastrointestinal disorder.

Interventions 1. Standard fast + Ranitidine [2 mg/kg] 2 hrs preop (n = 15)

2. Orange juice [5 ml/kg] + Ranitidine [2 mg/kg] 2 hrs preop (n = 18)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Marker dye [ phenolsulfonphthalein - PSP].

Notes Assessor blinding unclear. Max juice intake for patients > 30 kg was 150 ml. Eleven protocol deviations

(ingestion-surgery interval < 90mins). No gastric pH value for four participants. Premedication - none.


Study Sarti 1991


Participants 62 children, 1-12 years, elective urological surgery. Exclusions: premedicated, prior surgery.


2. Water or apple juice [unlimited] up to 2hrs preop (n= 32)


Notes Standard Fast = NPO from midnight. Assessor blinding unclear. Premedication - none.


Study Schreiner 1990

Methods RCT (shuffled opaque sealed envelopes)

Participants 121 children, 1-18 years, ASA I-II, outpatients (or admitted on day of ) elective surgery. Exclusions; medi-

cations or disease known to delay gastric emptying or increase acid production.


2. Clear fluids [unlimited] up to 2 hrs preop (n = 53)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Compliance with fasting instructions, Irri-

tability, Tolerance of preop experience, comparison with other preoperative experiences (parent). Adverse

events.

Notes Standard Fast = after 8pm only clear fluids [unlimited] until 6hrs (< 5yrs) or 8hrs (> 5yrs). For intervention

group final clear fluid ingestion limited to < 8oz (approx 237 ml). One gastric sample unobtainable. Five

mishandled samples. No gastric pH values for thirty-two participants. Assessor blinding adequate. Premedi-

cation - (as required) meperidine, diazepam and atropine.


Study Splinter 1989


Participants 80 children, 5-10 years, ASA I-II, elective surgery. Exclusions; history of gastrointestinal disease, taking

medication known to affect gastric contents.


2. Apple Juice [3ml/kg] 2.5hrs preop (n = 40)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Thirst, Hunger. Adverse events.

Notes Standard Fast = NPO from midnight. Three children (< 5yrs) unable to answer questionnaire. Assessor

blinding adequate. Premedication- none.





Study Splinter 1990a


Participants 61 children, 5-10 years, ASA I-II, elective surgery. Exclusions; history of gastrointestinal disease or medication

known to affect gastric contents.


2. Apple Juice [6 ml/kg] 2.5 hrs preop (n = 30)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Thirst, Hunger, Behaviour. Adverse events.

Notes Standard Fast = NPO from midnight. Assessor blinding adequate. Premedication - unclear.


Study Splinter 1990b







Notes Standard Fast = NPO from midnight. Assessor blinding adequate. Premedication - unclear. Children in

group 1 were heavier than children in group 2.


Study Splinter 1990c




Interventions 1. Apple Juice [6 ml/kg] 2.5 hrs preop (n = 30)



Notes Standard Fast = NPO from midnight. Assessor blinding adequate. Premedication - unclear. Children in

group 1 were heavier than those in group 2.


Study Splinter 1991


Participants 152 adolescents, 13-19 years, ASA I-II, elective. Exclusions: history of gastrointestinal disease, medication

affected gastric contents.


2. Clear fluids [unlimited] up to 3 hrs preop (n = 76)

Outcomes Gastric volume - post induction Gastric pH - post induction Thirst, Hunger.

Notes Standard Fast = NPO from midnight. Assessor blinding adequate. Premedication - unclear.


Study Splinter Schaefer 1a





Participants 80 children, 2-12 years, ’healthy’, elective in- and outpatients. Exclusions; history of gastrointestinal disease

or medication (including premedications) affecting gastric contents.

Interventions 1. Clear Fluids [unlimited] up to 3 hrs preop (n = 40)

2. Clear Fluids [unlimited] up to 2.5 hrs preop (n = 40)


Notes RCT(Phase I) Assessor blinding adequate. Premedication- none.


Study Splinter Schaefer 1b


Participants 148 children, 2-12 years, ’healthy’, elective in- and outpatients. Exclusions; history of gastrointestinal disease

or medication (including premedications) affecting gastric contents.

Interventions 1. Clear Fluids [unlimited] up to 3 hrs preop (n = 74)

2. Clear Fluids [unlimited] up to 2 hrs preop (n = 74)


Notes RCT (Phase II). Assessor blinding adequate. Premedication - none.


Study Splinter Schaefer 2


Participants 121 children, 2-12 years, ASA I-II, elective (mainly ENT) surgery. Exclusions; history of gastrointestinal

disease, receiving medication known to affect gastric contents.


2. Clear Fluids [unlimited] up to 3 hrs preop (n = 57)


Notes Standard Fast = NPO from midnight. Assessor blinding adequate. Premedication - none.


Study Splinter Schaefer 3a


Participants 100 children, 0-24mths, ASA I-II, elective surgery. Exclusions; history of gastrointestinal disease, receiving


Interventions 1. Clear fluids [unlimited] 3 hrs preop (n = 50)



Notes Participants permitted bottled milk/formula up to 6 hrs preop. Breast milk up to 4 hrs preop. Assessor

blinding adequate. Premedication - not reported


Study Splinter Schaefer 3b




Interventions 1. Clear fluids [unlimited] 3 hrs preop (n = 50)




2. Clear fluids [unlimited] 2.5 hrs preop (n = 50)





Study Splinter Schaefer 3c




Interventions 1. Clear fluids [unlimited] 2.5 hrs preop (n = 50)






Study Welborn 1993

Methods RCT (day of the week)

Participants 200 children, 1-10 years, outpatients, elective surgery (including hernia repair, circumcision, ochidopexy,

eye muscle). Exclusions; not listed.


2. Apple juice [10 ml/kg] 2 hrs preop (n = 87)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Blood glucose.

Notes Standard Fast = clear fluids up to 6 hrs preop then NPO. Gastric aspirate only available for 84 participants.

Assessor blinding unclear. Premedication - none. IV fluids - all patients.


Study van der Walt 1986a


Participants 63 children, 5 days -12 mths, ’healthy’, elective ’routine’ surgery. Exclusions; feeding problems, gastrointestinal

disorders, IV fluids.


2. Poly-joule (20%) [10 ml/kg] 3hrs preop (n = 30)

Outcomes Gastric volume - post induction. Gastric pH - post induction. Plasma glucose concentration, blood acid-

base value. Adverse events.

Notes Standard Fast = normal feeding up to four hours preop then NPO. Assessor blinding adequate. Premedication

- none.


Study van der Walt 1986b








2. Dextrose Solution (5%) [10 ml/kg] 3 hrs preop (n = 29)




- none.


Study van der Walt 1986c





2. Cows’ milk [10 ml/kg] 3 hrs preop (n = 31)




- none.


Study van der Walt 1986d




Interventions 1. Dextrose (5%) [10 ml/kg] 3 hrs preop (n = 29)

2. Poly-joule (20%) [10 ml/kg] 3 hrs preop (n = 30)



Notes Assessor blinding adequate. Premedication - none.


Study van der Walt 1986e




Interventions 1. Dextrose (5%) [10 ml/kg] 3 hrs preop (n = 29)






Study van der Walt 1986f




Interventions 1. Poly-joule (20%) [10 ml/kg] 3 hrs preop (n = 30)









Characteristics of excluded studies

Bevan & Burn 1973 Query random allocation. Outcome measures addressed - acid-base and blood glucose levels.

Bevan & Burn 1973b Query random allocation. Outcome measures addressed - acid-base and blood glucose levels.

Fry 1976 Outcome measures addressed - hypoglycaemia and blood glucose levels.

Graham 1979 Non-RCT. Plasma glucose concentration.

Hotta 1967 Data relevant to this review could not be extracted.

Ingebo 1997 Observational.

Jensen 1982 Outcome measures addressed - blood glucose concentrations.

Litman 1994 Non-random allocation.

Morrice 1974 Outcome measures addressed - blood glucose concentrations.

Niija 1999 Query random allocation. Outcome measures addressed - blood glucose, blood ketone body, plasma free fatty

acids (NEFA), insulin, glucagon and cortisol.

Nilsson 1984 Observational

O’Flynn 1989 Observational

Sandstrom 1993 Non-random allocation. (Also reported in part in Larsson, Nilsson, Niklasson, Andresson and Ekström-Jodal,

British Journal of Anaesthesia 1990; 64:419-424).

Schneider 1982 Outcome addressed - plasma glucose

Schurizek 1986 Observational. Based on emergency admissions.

Sethi 1999 Addresses gastric emptying times and the methodology of sampling the volume of intra-operative gastric

contents.

Stanley 1989 Lollipop based intervention not included in fluid/solid preoperative intake addressed by this review.

Thomas 1974 Hypoglycaemia

Watson 1972 Blood Glucose

NOTE - this table does not include those trials presented within the review Preoperative Fasting for adults to

prevent perioperative complications Brady et al 2004.

van der Walt 1990 Non-random allocation.



A D D I T I O N A L T A B L E S

Table 01. Guidelines for Paediatric Preoperative Fasting

Age Group Solids Clear Fluids Breast Milk Non-human Milk+form

Neonates < 6 mths N/A 2 hrs * † 4 hrs * (†milk type not

specified)

6 hrs *

4 hrs †(milk type not

specified)

Infants

6-36mths

6 hrs† 2 hrs * † 4 hrs *

6 hrs † (milk type not

specified)

6 hrs *(†milk type not

specified)

Children

>36mths

6 hrs *

8 hrs †

2 hrs * † 4 hrs *

8 hrs † (milk type not

specified)

6 hrs *

8 hrs †

KEY hrs = recommended

duration of preoperative

fasting measured in hours

* = American Society of

Anesthesiologists (1999)

† = American Academy of

Pediatricians (1992)

Table 02. The ASA Physical Status Classification System

Class I Class II Class III Class IV Class V Class VI

A normally healthy

patient

A patient with mild

systemic disease

A patient with

severe systemic

disease

A patient with

severe systemic

disease that is a

constant threat to

life

A moribund patient

who is not expected

to survive 24

hrs without the

operation

A declared brain-

dead patient whose

organs are being

removed (for)

donor purposes



Tab

le03.

Sea

rch

stra

tegy

for

elec

tron

icd

atab

ases

Dat

abas

eSt

rate

gy

Med

lin

e19

66-

Au

gust

2003

1.(r

and

omiz

ed-c

ontr

olle

d-t

rial

orm

eta-

anal

ysis

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ntr

olle

dcl

inic

altr

ial)

.pt.

2.(R

and

om$

orm

eta-

anal

$or

met

aan

aly$

orm

eta

anal

y$).

tw.

3.((

dou

bl$

orsi

ngl

$)an

dbl

ind

$).t

w.

4.ex

pC

lin

ical

-Tri

als/

5.cr

osso

ver.

ti,a

b,tw

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or2

or3

or4

or5

7.ad

ult

$.m

p.

8.(A

nes

th$

orA

nae

sth

$).a

f.

9.an

esth

esia

/or

anes

thes

iolo

gy/

oran

aest

hes

ia/

oran

aest

hes

iolo

gy/

10.

An

esth

esia

,C

ond

uct

ion

/or

anes

thes

ia,

gen

eral

/or

anes

thet

ics

inh

alat

ion

/or

anes

thet

ics

dis

soci

ativ

e/or

anes

thes

ia

intr

atra

chea

l/or

anes

thes

iain

trav

enou

s/or

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thes

iacl

osed

circ

uit

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anes

thes

iaob

stet

rica

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anes

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ia,

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very

per

iod

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esia

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enta

l/or

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iad

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tmen

t,h

osp

ital

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anes

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iain

hal

atio

n/

orad

juva

nts

,an

esth

esia

/or

intr

aop

erat

ive

com

pli

cati

ons.

mp.

11.

exp

An

esth

esia

,C

ond

uct

ion

/or

exp

anes

thes

ia,

gen

eral

/or

exp

anes

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ics

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alat

ion

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exp

anes

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ics

dis

soci

ativ

e/or

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anes

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iain

trat

rach

eal/

orex

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esth

esia

intr

aven

ous/

orex

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esia

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edci

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it/

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etri

cal/

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anes

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ecov

ery

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enta

l/or

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anes

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epar

tmen

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ital

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atio

n/

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esia

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(pre

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orp

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p$

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rg$

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urg

$or

pre

anae

st$

orp

re-a

nae

st$

orp

rean

est$

orp

re-a

nes

t$).

af.

13.

8or

9or

10or

11or

12

14.

(fas

t$or

star

v$).

af.

15.

13an

d14

and

6

16.

15n

ot7

17.

lim

it16

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um

an

18.

(flu

id$

ord

rin

k$or

dig

est$

orin

take

orh

ydra

t$).

af.

19.

18an

d13

and

6

20.

19an

d7

21.

lim

it20

toh

um

an

22.

(foo

dor

eat$

orn

utr

itio

n).

mp.

23.

22an

d13

and

6

24.

23n

ot7

25.

lim

it24

toh

um

an

26.

(th

irst

$or

hu

ng$

).m

p.

27.

26an

d13

and

6

28.

27n

ot7

29.

lim

it28

toh

um

an



Tab

le03.

Sea

rch

stra

tegy

for

elec

tron

icd

atab

ases

(Con

tinu

ed)

Dat

abas

eSt

rate

gy

30.

(pre

oper

ativ

efa

st$

orp

re-o

per

ativ

efa

st$)

.af.

31.

30n

ot7

32.

lim

it31

toh

um

an

33.

(Nil

bym

outh

orN

PO

orN

ull

ap

eros

orN

oth

ing

bym

outh

).af

.

34.

33n

ot7

35.

lim

it34

toh

um

an

36.

PN

EU

MO

NIA

/or

PN

EU

MO

NIA

,A

SPIR

AT

ION

/or

PN

EU

MO

NIA

,B

AC

TE

RIA

L/

orP

NE

UM

ON

IA,

LIP

ID/

or

PN

EU

MO

NIA

,MY

CO

PL

ASM

A.m

p.[m

p=t

itle

,ab

stra

ct,

cas

regi

stry

/ec

nu

mbe

rw

ord

,m

esh

subj

ect

hea

din

g]

37.

(pn

eum

onia

oras

pir

atio

n).

af.

38.

RIS

K/

orR

ISK

ASS

ESS

ME

NT

/or

RIS

KFA

CT

OR

S/or

RIS

KM

AN

AG

EM

EN

T/

39.

36or

37or

38

40.

39an

d13

and

6

41.

40n

ot7

42.

lim

it41

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um

an

43.

Hyd

roge

n-I

onC

once

ntr

atio

n/

44.

Stom

ach

/

45.

(gas

tric

orst

omac

hor

ph

orvo

lum

e).m

p.

46.

exp

intr

aop

erat

ive

com

pli

cati

ons/

orex

pp

osto

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ativ

eco

mp

lica

tion

s/or

exp

pre

oper

ativ

eca

re/

47.

(pre

oper

ativ

eca

reor

pos

top

erat

ive

com

pli

cati

ons

orin

trao

per

ativ

eco

mp

lica

tion

s).a

f.

48.

43or

44or

45

49.

46or

47

50.

48an

d49

and

13an

d6

51.

50n

ot7

52.

lim

it51

toh

um

an

53.

17an

d21

and

25an

d19

and

32an

d35

and

42an

d52

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AH

L19

82-t

oA

ugu

st20

031.

(ran

dom

ized

-con

trol

led

-tri

alor

met

a-an

alys

isor

con

trol

led

clin

ical

tria

l).p

t.

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and

om$

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anal

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ngl

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dbl

ind

$).t

w.

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pC

lin

ical

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als/

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osso

ver.

ti,a

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7.(A

nes

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nae

sth

$).a

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esth

esia

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anes

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iolo

gy/

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ia/

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gy/

9.A

nes

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ia,

Con

du

ctio

n/

oran

esth

esia

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ner

al/

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etic

sin

hal

atio

n/

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etic

sd

isso

ciat

ive/

oran

esth

esia

intr

atra

chea

l/or

anes

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iain

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enou

s/or

anes

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osed

circ

uit

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anes

thes

iaob

stet

rica

l/or

anes

thes

ia,

reco

very

per

iod

/



Tab

le03.

Sea

rch

stra

tegy

for

elec

tron

icd

atab

ases

(Con

tinu

ed)

Dat

abas

eSt

rate

gy

oran

esth

esia

,d

enta

l/or

anes

thes

iad

epar

tmen

t,h

osp

ital

/or

anes

thes

iain

hal

atio

n/

orad

juva

nts

,an

esth

esia

/or

intr

aop

erat

ive

com

pli

cati

ons.

mp.

10.

(pre

op$

orp

re-o

p$

orp

resu

rg$

orp

re-s

urg

$or

pre

anae

st$

orp

re-a

nae

st$

orp

rean

est$

orp

re-a

nes

t$).

af.

11.

7or

8or

9or

10

12.

(fas

t$or

star

v$).

af.

13.

11an

d12

14.

(flu

id$

ord

rin

k$or

dig

est$

orin

take

orh

ydra

t$).

af.

15.

14an

d11

16.

(foo

dor

eat$

orn

utr

itio

n).

mp.

17.

16an

d11

18.

(th

irst

$or

hu

ng$

).m

p.

19.

18an

d11

20.

(pre

oper

ativ

efa

st$

orp

re-o

per

ativ

efa

st$)

.af.

21.

(Nil

bym

outh

orN

PO

orN

ull

ap

eros

orN

oth

ing

bym

outh

).af

.

22.

pn

eum

onia

/or

pn

eum

onia

,as

pir

atio

n/

orp

neu

mon

ia,

bact

eria

l/or

pn

eum

onia

,li

pid

/or

pn

eum

onia

,m

ycop

lasm

a.m

p.

[mp

=tit

le,

cin

ahl

subj

ect

hea

din

gs,

abst

ract

,in

stru

men

tati

on]

23.

(pn

eum

onia

oras

pir

atio

n).

af.

24.

risk

/or

risk

asse

ssm

ent/

orri

skfa

ctor

s/or

risk

man

agem

ent/

25.

22or

23or

24

26.

25an

d11

and

6

27.

Hyd

roge

n-I

onC

once

ntr

atio

n/

28.

Stom

ach

/

29.

(gas

tric

orst

omac

hor

ph

orvo

lum

e).m

p.

30.

exp

intr

aop

erat

ive

com

pli

cati

ons/

orex

pp

osto

per

ativ

eco

mp

lica

tion

s/or

exp

pre

oper

ativ

eca

re/

31.

(pre

oper

ativ

eca

reor

pos

top

erat

ive

com

pli

cati

ons

orin

trao

per

ativ

eco

mp

lica

tion

s).a

f.

32.

27or

28or

29

33.

30or

31

34.

32an

d33

and

11

35.

13or

15or

17or

19or

20or

21or

26or

34

Coc

hra

ne

Cen

tral

Reg

iste

rof

Con

trol

led

Tri

als

1.FA

STIN

Gex

plo

de

allt

rees

(MeS

H)

2.F

LU

IDT

HE

RA

PY

sin

gle

term

(MeS

H)

3.fa

stin

g

4.st

arv*

5.(fl

uid

ord

rin

k*)

6.(o

ral

and

inta

ke*)



Tab

le03.

Sea

rch

stra

tegy

for

elec

tron

icd

atab

ases

(Con

tinu

ed)

Dat

abas

eSt

rate

gy

7.h

ydra

t*

8.(f

ood

orea

t*or

nu

trit

ion

*)

9.((

nil

nex

tby

nex

tm

outh

)or

(not

hin

gn

ext

byn

ext

mou

th)

or(n

ull

an

ext

per

nex

tos

)or

np

o)

10.

(#1

or#2

or#3

or#4

or#5

or#6

or#7

or#8

or#9

)

11.

AN

EST

HE

SIA

exp

lod

etr

ee1

(MeS

H)

12.

PR

EO

PE

RA

TIV

EC

AR

Esi

ngl

ete

rm(M

eSH

)

13.

PE

RIO

PE

RA

TIV

EC

AR

Eex

plo

de

allt

rees

(MeS

H)

14.

(an

aest

hes

i*or

anes

thes

i*)

15.

(pre

anae

sth

esi*

orp

rean

esth

esi*

)

16.

((p

ren

ext

anae

sth

esi*

)or

(pre

nex

tan

esth

esi*

))

17.

((p

ren

ext

oper

at*)

orp

reop

erat

*)

18.

((p

ren

ext

surg

*)or

pre

surg

*)

19.

(#11

or#1

2or

#13

or#1

4or

#15

or#1

6or

#17

or#1

8)

20.

(#10

and

#19)

21.

PN

EU

MO

NIA

exp

lod

eal

ltre

es(M

eSH

)

22.

pn

eum

onia

23.

asp

irat

ion

24.

(((p

ost

nex

top

erat

ive)

orp

osto

per

ativ

e)an

dco

mp

lica

tion

*)

25.

(pos

tan

dop

erat

*an

din

fect

ion

*)

26.

(pos

top

erat

ive

and

infe

ctio

n*)

27.

PO

STO

PE

RA

TIV

EC

OM

PL

ICA

TIO

NS

exp

lod

eal

ltre

es(M

eSH

)

28.

(((p

erin

ext

oper

ativ

e)or

per

iop

erat

ive)

and

com

pli

cati

on*)

29.

(((i

ntr

an

ext

oper

ativ

e)or

intr

aop

erat

ive)

and

com

pli

cati

on*)

30.

(su

rg*

nea

rco

mp

lica

tion

*)

31.

(op

erat

ion

*n

ear

com

pli

cati

on*)

32.

(#21

or#2

2or

#23

or#2

4or

#25

or#2

6or

#27

or#2

8or

#29

or#3

0or

#31)

33.

(#20

and

#32)

34.

(ch

ild

orch

ild

ren

)

35.

CH

ILD

exp

lod

etr

ee1

(MeS

H)

36.

(ped

iatr

ics

orp

aed

iatr

ics)

37.

(#34

or#3

5or

#36)

38.

(#33

and

#37)

39.

fast

ing:

ti

40.

(#39

and

#19)

41.

(#39

and

#32)

42.

(#39

and

#37)



Tab

le03.

Sea

rch

stra

tegy

for

elec

tron

icd

atab

ases

(Con

tinu

ed)

Dat

abas

eSt

rate

gy

43.

(#38

or#4

0or

#41

or#4

2)



Table 04. Participants’ Age and Paediatric Age Groups

Trial Neonate (< 1mth) Infant (1-12 mth) Child (> 12 mths) Adolescent (12-18 y)

Cook-Sather 2003 0-9 months 0-9 months

Splinter Schafer 3 0-24 months 0-24 months 0-24 months

van der Walt 1986 5 days - 3 months 5 days - 3 months

Miller 1990 1 month - 5 years 1 month - 5 years

Nicolson 1992 * * *

Aun 1990 1-5 years

Gombar 1997 2-12 years

Goresky 1992 1-6 years

Kushikata 1996 5-12 years

Moyao-García 2001 3-12 years

Splinter 1989 5-10 years

Splinter 1990 5-10 years

Splinter Schafer 1a 2-12 years

Splinter Schafer 1b 2-12 years

Splinter Schafer 2 2-12 years

Welborn 1993 1-10 years

Sarti 1991 1-12 years

Crawford 1990 1-14 years 1-14 years

Maekawa 1993 1-14 years 1-14 years

Meakin 1985 1-16 years 1-16 years

Sandhar 1989 1-14 years 1-14 years

Schreiner 1990 1-18 years 1-18 years

Splinter 1991 13-19 years 13-19 years

* Participants exact age range unavailable though children < 6 months and > 5 years were included. Mean age ± SD for the two groups

was 3.1 ± 4.1 and 3.3 ± 3.9.

Table 05. Details of Quality Evaluation by Trial

Trial

Reference

Partici-

pants

Inclusion

criteria

Exclusion

criteria

A priori

sample

size

Random

Sequence

Con-

cealed

Allocation

Group

Compara-

bility Blinding

ITT

analysis

Aun 1990

(published

20

children in

Listed Listed Not

Reported

Adequate Adequate Yes (age,

weight)

Adequate Not

reported



Table 05. Details of Quality Evaluation by Trial (Continued )

Trial

Reference

Partici-

pants

Inclusion

criteria

Exclusion

criteria

A priori

sample

size

Random

Sequence

Con-

cealed

Allocation

Group

Compara-

bility Blinding

ITT

analysis

& unpub-

lished in-

formation)

two arms (four par-

ticipants

no pH

values

values)

Cook-

Sather

2003

(published

& unpub-

lished in-

formation)

97

children in

two arms

Listed Listed Yes Adequate Adequate Yes (age,

weight,

gender,

volume of

feed)

Adequate No (per

protocol

analysis)

ITT

analysis

described

but results

not

reported

Crawford

1990

(published

& unpub-

lished in-

formation)

100

children in

three arms

Listed Listed Not

Reported

Adequate Unclear Unclear Adequate Not

Reported

Gombar

1997

(published

& unpub-

lished in-

formation)

50

children in

two arms

Listed Listed Not

Reported

Adequate Unclear Standard

Fast group

older,

heavier,

more

females

less male

partici-

pants than

the group

given fluid

preopera-

tively

Unclear -

Adequate

for assessor

involved

with

collecting

thirst and

behaviour

reports

Not

Reported

(one

participant

no pH

value)

Goresky

1992

240

children in

four arms

Listed Listed Not

Reported

Unclear Unclear Yes (age,

weight,

gender,

height)

Unclear -

Adequate

for

ranitidine/

placebo

interven-

tion

Not

Reported

(41 par-

ticipants

no pH

values or

protocol

deviation)

Kushikata

1996

(published

20

children in

two arms

Listed Not Listed Not

Reported

Inade-

quate

Inade-

quate

Yes (age,

weight,

volume of

Unclear Not

Reported




Trial

Reference

Partici-

pants

Inclusion

criteria

Exclusion

criteria

A priori

sample

size

Random

Sequence

Con-

cealed

Allocation

Group

Compara-

bility Blinding

ITT

analysis

& unpub-

lished in-

formation)

ingested

fluids)

Maekawa

1993

(published

& unpub-

lished in-

formation)

105

children in

three arms

Listed Listed Not

Reported

Unclear Unclear Yes (age,

weight,

volume of

ingested

fluids)

Adequate Not

Reported

(28 partic-

ipants no

pH values)

Meakin

1987

(published

& unpub-

lished in-

formation)

116

children in

five arms

Listed Listed Not

Reported

Inade-

quate

Inade-

quate

Yes (age,

weight)

Unclear -

Adequate

for pH

and food

particle

measures

Not

Reported

(23 partic-

ipants no

pH values)

Miller

1990

44

children in

two arms

Listed Listed Not

Reported

Adequate Unclear Yes (age,

weight)

Unclear Not

Reported

(23 par-

ticipants

gastric

aspirate

unavail-

able)

Moyao-

García

2001

40

children in

two arms

Listed Listed Not

Reported


weight,

gender)

Adequate Not

Reported

(no with-

drawals)

Nicolson

1992

100

children in

two arms

Listed Listed Not

Reported

Unclear Adequate Yes (age,

weight,

gender,

ASA

status,

type of

cardiac

procedure)

Adequate Not

Reported

(54 partic-

ipants no

pH values)

Sandhar

1989

88

children in

four arms

Listed Listed Not

Reported


weight,

fast to

interven-

tion)

Unclear Not

Reported

(23

protocol

deviations,

seven no

gastric

aspirate)

Sarti 1991 62 Listed Not Listed Not Unclear Unclear Yes (age, Unclear Not




Trial

Reference

Partici-

pants

Inclusion

criteria

Exclusion

criteria

A priori

sample

size

Random

Sequence

Con-

cealed

Allocation

Group

Compara-

bility Blinding

ITT

analysis

children in

two arms

Reported ASA

status)

Reported

(no with-

drawals)

Schreiner

1990

121

children in

two arms

Listed Listed Not

Reported


weight,

gender)

Adequate Not

Reported

(32 partic-

ipants no

pH values,

six samples

mishan-

dled)

Splinter

1989

(published

& unpub-

lished in-

formation)

80

children in

two arms

Listed Listed Not

Reported


gender,

ASA

status)

Adequate Not

Reported

(no with-

drawals)

Splinter

1990

(published

& unpub-

lished in-

formation)

93

children in

three arms

Listed Listed Yes Adequate Unclear 10 ml/kg

group

lighter

than 6

ml/kg and

control

groups.

Groups

compa-

rable in

terms

of age,

gender,

ASA

status.

Adequate Not

Reported

(no with-

drawals)

Splinter

1991

(published

& unpub-

lished in-

formation)

152 ado-

lescents in

two arms

Listed Listed Not

Reported


weight,

gender,

ASA

status,

in/out

patient

status)

Adequate Not

reported

(no with-

drawals)

Splinter

Schaefer

1a

(published

80

children in

two arms

Listed Listed Yes Adequate Unclear Yes (age,

weight,

gender,

ASA

Adequate Not

reported

(no with-

drawals)




Trial

Reference

Partici-

pants

Inclusion

criteria

Exclusion

criteria

A priori

sample

size

Random

Sequence

Con-

cealed

Allocation

Group

Compara-

bility Blinding

ITT

analysis

& unpub-

lished in-

formation)

status)

Splinter

Schaefer

1b

(published

& unpub-

lished in-

formation)

148

children in

two arms


weight,

gender,

ASA

status)

Adequate Not

reported

(no with-

drawals)

Splinter

Schaefer 2

(published

& unpub-

lished in-

formation)

121

children in

two arms


weight,

gender,

ASA

status)

Adequate Not

reported

(no with-

drawals)

Splinter

Schaefer 3

(published

& unpub-

lished in-

formation)

150

children in

three arms

Listed Listed Not

Reported


weight,

gender,

ASA

status,

in/out

patient

status,

milk

ingestion,

volume of

clear fluid

ingestion)

Adequate Not

reported

(no with-

drawals

reported)

van der

Walt 1986

(published

& unpub-

lished in-

formation)

123

children in

four arms

Listed Listed Not

Reported

Adequate Unclear Unclear

(age), No

(weight)

Adequate Not

reported

(64 partic-

ipants no

pH value)

Welborn

1993

200

children in

two arms

Listed Not Listed Not

Reported

Inade-

quate

Inade-

quate

Yes (age,

weight,

preop,

induction

and

postop

blood

glucose)

Unclear Not

reported

(116 par-

ticipants

no gastric

sample)



Table 06. Summary Statistics - Gastric Volume (ml/kg) - Intervention Groups

Trial ref

No. of Par-

ticipants Mean

Standard

Deviation Median Minimum Maximum

Std. Error

of Mean

Pseudo-

Mean

Pseudo-Std

Dev

Splinter

1990a

30 0.66 0.79 0.37 0.01 4.08

Splinter

1990b

32 0.71 0.76 0.47 0.01 3.69

Splinter

1990c

32 0.71 0.76 0.76 0.01 3.69

Splinter

Schafer 2

57 0.34 0.28 0.27 0.03 1.53

Gombar

1997

25 0.34 0.18 0.0 0.88

Maekawa

1993a

35 0.39 0.46 0.0 1.63

Maekawa

1993b

35 0.35 0.36 0.0 1.30

Maekawa

1993c

35 0.39 0.46 0.0 1.63

Nicolson

1992

44 0.6 0.9 0.0 4.0

Schreiner

1990

48 0.44 0.51 0.0 2.23

Splinter

1989

40 0.24 0.31 0.01 1.39

Splinter

1991

76 0.46 0.39 0.02 1.47

Splinter

Schafer 1a

40 0.37 0.37 0.02 1.54

Splinter

Schafer 1b

74 0.33 0.49 0.02 2.81

Splinter

Schafer 3a

50 0.21 0.37 0.04 2.37

Splinter

Schafer 3b

50 0.15 0.14 0.03 0.52

Splinter

Schafer 3c

50 0.21 0.37 0.04 2.37

Cook-

Sather 2003

36 0.16 0.30

Meakin

1985a

35 0.37 0.35 0.06

Meakin

1985b

32 0.46 0.34 0.06

Meakin

1985c

32 0.46 0.34 0.06



Meakin

1985d

14 0.30 0.30 0.08

Meakin

1985e

15 0.26 0.31 0.08

Meakin

1985f

14 0.30 0.30 0.08

Kushikata

1996

10 0.55 0.59

Miller 1990 19 0.23 0.21

Moyao-

García

2001

20 0.40 0.29

Sarti 1991 32 0.44 0.37

Aun 1990 10 0.53 0.0 2.9 1.00

Sandhar

1989a

13 0.34 0.0 1.0 0.30

Sandhar

1989b

18 0.17 0.0 0.7 0.20

Welborn

1993

41 0.08 0.0 0.80 0.18

van der

Walt 1986a

30 0.0 0.71 0.36 0.33

van der

Walt 1986b

29 0.0 0.77 0.38 0.37

van der

Walt 1986c

31 0.0 1.66 0.83 0.80

van der

Walt 1986d

[F1]

29 0.0 0.77 0.39 0.36

van der

Walt 1986e

[F1]

29 0.0 0.77 0.39 0.36

van der

Walt 1986f

[F1]

30 0.0 0.71 0.36 0.34

Crawford

1990a

group

specific data

unavailable

Crawford

1990b

group

specific data

unavailable

Crawford

1990c

group

specific data

unavailable



Table 06. Summary Statistics - Gastric Volume (ml/kg) - Intervention Groups (Continued )

Trial ref

No. of Par-

ticipants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-Std

Dev

Goresky

1992a

group

specific data

unavailable

Goresky

1992b

group

specific data

unavailable

Table 07. Summary Statistics - Gastric Volume (ml/kg) - Control Group

Trial ref

No. of Par-

ticipants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-Std

Deviation

Splinter

1990a

31 0.45 0.31 0.45 0.02 1.15

Splinter

1990b

31 0.45 0.31 0.45 0.02 1.15

Splinter

1990c

32 1.8 0.8 1.6 1.2 6.0

Splinter

Schafer 2

64 0.39 0.37 0.29 0.04 1.97

Gombar

1997

25 0.38 0.25 0.07 1.35

Maekawa

1993a

35 0.36 0.42 0.0 1.64

Maekawa

1993b

35 0.36 0.42 0.0 1.64

Maekawa

1993c

35 0.35 0.36 0.0 1.30

Nicolson

1992

47 0.4 0.6 0.0 3.0

Scheiner

1990

67 0.57 0.51 0.0 2.09

Splinter

1989

40 0.43 0.46 0.01 1.65

Splinter

1991

76 0.48 0.40 0.02 2.11

Splinter

Schafer 1a

40 0.38 0.30 0.02 1.31

Splinter

Schafer 1b

74 0.27 0.30 0.02 1.81

Splinter

Schafer 3a

50 0.25 0.80 0.03 5.78



Table 07. Summary Statistics - Gastric Volume (ml/kg) - Control Group (Continued )

Trial ref

No. of Par-

ticipants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-Std

Deviation

Splinter

Schafer 3b

50 0.25 0.80 0.03 5.78

Splinter

Schafer 3c

50 0.15 0.14 0.03 0.52

Moyao-

García

2001

20 0.78 0.44

Meakin

1985a

20 0.21 0.31 0.07

Meakin

1985b

20 0.21 0.31 0.07

Meakin

1985c

35 0.37 0.35 0.06

Meakin

1985d

15 0.26 0.31 0.08

Meakin

1985e

20 0.21 0.31 0.07

Meakin

1985f

20 0.21 0.31 0.07

Cook-

Sather 2003

31 0.19 0.38

Kushikata

1996

10 0.43 0.32

Miller 1990 25 0.41 0.34

Sarti 1991 30 0.38 0.30

Aun 1990 10 0.16 0.0 0.47 0.15

Sandhar

1989a

19 0.25 0.0 1.1 0.30

Sandhar

1989b

15 0.16 0.0 0.6 0.18

Welborn

1993

43 0.08 0.0 0.86 0.21

van der

Walt 1986a

33 0.0 1.5 0.75 0.67

van der

Walt 1986b

33 0.0 1.5 0.75 0.67

van der

Walt 1986c

33 0.0 1.5 0.75 0.67

van der 30 0.0 0.71 0.36 0.33



Table 07. Summary Statistics - Gastric Volume (ml/kg) - Control Group (Continued )

Trial ref

No. of Par-

ticipants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-Std

Deviation

Walt 1986d

[F2]

van der

Walt 1986e

[F2]

31 0.0 1.66 0.83 0.79

van der

Walt 1986f

[F2]

31 0.0 1.66 0.83 0.81

Crawford

1990a

group

specific data

unavailable

Crawford

1990b

group

specific data

unavailable

Crawford

1990c

group

specific data

unavailable

Goresky

1992a

group

specific data

unavailable

Goresky

1992b

group

specific data

unavailable

Table 08. Summary Statistics - Gastric pH - Intervention Groups

Trial ref

No. of

Partici-

pants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-

Std

Deviation

Splinter

1990a

30 1.7 0.6 1.5 1.3 4.2

Splinter

1990b

32 1.8 0.8 1.6 1.2 6.0

Splinter

1990c

32 1.8 0.8 1.6 1.2 6.0

Splinter

Schafer 2

57 1.8 0.7 1.6 1.2 5.0

Gombar

1997

24 2.53 0.79 1.22 4.52

Maekawa

1993a

27 1.67 0.65 0.9 3.7



Table 08. Summary Statistics - Gastric pH - Intervention Groups (Continued )

Trial ref

No. of

Partici-

pants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-

Std

Deviation

Maekawa

1993b

25 1.75 0.61 1.1 3.4

Maekawa

1993c

27 1.67 0.65 0.9 0.65

Splinter

1989

40 2.2 1.2 1.1 7.0

Splinter

1991

76 1.80 1.00 1.20 6.50

Splinter

Schafer 1a

40 1.9 1.0 1.2 7.0

Splinter

Schafer 1b

74 1.8 1.0 1.3 7.0

Splinter

Schafer 3a

50 2.4 1.3 1.2 7.0

Splinter

Schafer 3b

50 2.3 1.3 1.2 6.0

Splinter

Schafer 3c

50 2.4 1.3 1.2 7.0

Goresky

1992a

48 1.96 1.18 0.17

Goresky

1992b

53 4.09 2.26 0.31

Cook-

Sather

2003

36 2.9 1.3

Kushikata

1996

10 1.89 0.75

Miller

1990

19 1.7 0.6

Moyao-

García

2001

20 3.18 0.61

Nicolson

1992

20 1.9 0.7

Sarti 1991 32 1.7 0.9

Schreiner

1990

35 1.81

(reported

as H ion

concentra-

tion 0.015

reported as

H ion con-

centration

0.008




Trial ref

No. of

Partici-

pants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-

Std

Deviation

Sandhar

1989a

12 1.83 0.9 3.6 0.85

Sandhar

1989b

15 4.76 2.0 7.7 1.63

Welborn

1993

41 1.45 1.3 1.6 0.07

Meakin

1985a

31 1.7 1.3 6.0 2.14 1.31

Meakin

1985b

29 1.8 1.4 5.5 2.20 1.11

Meakin

1985c

29 1.8 1.4 5.5 2.20 1.16

Meakin

1985d

10 1.9 1.6 2.5 1.96 0.31

Meakin

1985e

12 1.8 1.1 2.4 1.78 0.42

Meakin

1985f

10 1.9 1.6 2.5 1.96 0.31

van der

Walt

1986a

17 1.5 5.0 3.25 1.57

van der

Walt

1986b

15 1.5 3.5 2.50 0.89

van der

Walt

1986c

14 1.5 7.0 4.26 2.42

van der

Walt

1986d

[F1]

15 1.5 3.5 2.50 0.88

van der

Walt

1986e [F1]

15 1.5 3.5 2.50 0.89

van der

Walt 1986f

[F1]

17 1.5 5.0 3.25 1.56

Aun 1990 10 group

specific

data

unavailable




Trial ref

No. of

Partici-

pants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-

Std

Deviation

Crawford

1990b

group

specific

data

unavailable

Crawford

1990a

group

specific

data

unavailable

Crawford

1990c

group

specific

data

unavailable

Table 09. Summary Statistics - Gastric pH - Control Group

Trial ref

No. of

Partici-

pants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-

Std

Deviation

Splinter

1990a

31 1.7 0.6 1.5 1.2 4.0

Splinter

1990b

31 1.7 0.6 1.5 1.2 4.0

Splinter

1990c

30 1.7 0.6 1.5 1.3 4.2

Splinter

Schafer 2

64 1.7 0.4 1.6 1.1 4.0

Gombar

1997

25 2.26 0.57 1.17 3.65

Maekawa

1993a

25 1.72 0.48 1.0 2.8

Maekawa

1993b

25 1.72 0.48 1.0 2.8

Maekawa

1993c

25 1.75 0.61 1.1 3.4

Splinter

1989

40 1.7 0.6 1.2 4.5

Splinter

1991

76 1.60 0.40 1.20 3.0

Splinter

Schafer 1a

40 1.8 0.9 1.20 7.0

Splinter 74 1.9 1.0 1.2 6.0



Table 09. Summary Statistics - Gastric pH - Control Group (Continued )

Trial ref

No. of

Partici-

pants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-

Std

Deviation

Schafer 1b

Splinter

Schafer 3a

50 2.0 1.0 1.3 6.0

Splinter

Schafer 3b

50 2.0 1.0 1.3 6.0

Splinter

Schafer 3c

50 2.3 1.3 1.2 6.0

Goresky

1992a

51 1.94 0.93 0.13

Goresky

1992b

47 3.70 2.33 0.34

Cook-

Sather

2003

31 2.5 0.5

Kushikata

1996

10 1.43 0.27

Miller

1990

25 1.6 0.7

Moyao-

García

2001

20 1.75 0.38

Nicolson

1992

17 2.0 0.4

Sarti 1991 30 1.6 1.0

Schreiner

1990

48 1.77

(reported

as H ion

concentra-

tion 0.017)

reported as

H ion con-

centration

0.01

Sandhar

1989a

17 2.1 1.2 4.1 0.96

Sandhar

1989b

14 3.97 1.3 7.3 1.79

Welborn

1993

43 1.41 0.93 1.65 0.17

Meakin

1985a

14 1.8 1.5 2.4 1.85 0.29

Meakin

1985b

14 1.8 1.5 2.4 1.85 0.28




Trial ref

No. of

Partici-

pants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-

Std

Deviation

Meakin

1985c

31 1.7 1.3 6.0 2.14 1.32

Meakin

1985d

12 1.8 1.1 2.4 1.78 0.42

Meakin

1985e

14 1.8 1.5 2.4 1.85 0.28

Meakin

1985f

14 1.8 1.5 2.4 1.85 0.29

van der

Walt

1986a

13 1.5 7.0 4.27 2.69

van der

Walt

1986b

13 1.5 7.0 4.27 2.94

van der

Walt

1986c

13 1.5 7.0 4.25 2.90

van der

Walt

1986d

[F2]

17 1.5 5.0 3.25 1.58

van der

Walt

1986e [F2]

14 1.5 7.0 4.24 2.43

van der

Walt 1986f

[F2]

14 1.5 7.0 4.26 2.45

Aun 1990 10 not

reported

by group

Crawford

1990a

group

specific

data

unavailable

Crawford

1990b

group

specific

data

unavailable

Crawford

1990c

group

specific

data

unavailable




Trial ref

No. of

Partici-

pants Mean

Standard


Std. Error

of Mean

Pseudo-

Mean

Pseudo-

Std

Deviation

Table 10. Key to Secondary Outcome Data Tables

Key Measure Key Time of Measure

VAS Visual Analogue Scale (a) > or = 1 day preoperatively

Y/N/O Yes/No/No Opinion (b) on admission

1-3 1 to 3 Scale (1. Satisfied; 2. moderately satisfied; 3. very hungry). (c) prerandomisation

noted note taken of any occurrence (d) > or = 120 mins preoperatively

reported participant report (e) < 120 mins preoperatively

˙ not measured (f ) preinduction/in operating room

[c]/[p] Completed by child/parent (g) after child has departed for operating room

Table 11. Details of Particles Observed in Gastric Aspirates

Trial Comparison Observed Results

Cook-Sather 2003 1. Clear fluids [unlimited] up to 2 hrs (n =

36)

2. Formula [unlimited] up to 4 hrs pre op (n

= 31)

Yes Gastric aspirate tinged white (evidence of

formula) for 9 infants (including one fasted

for 10 hrs). Several small particles in one

child’s (from clear fluid group) clear gastric

aspirate.

Kushikata 1996 1. Standard Fast (n = 10)

2. Rice porridge [55 g rice + 245 mls water +

some salt] 330 mins preop + clear fluids [<

200 ml] up to 5 hrs preop (n = 10)

Yes No solid particles observed.

Maekawa 1993a 1. Standard Fast (n = 35)


Yes No particles observed.

Maekawa 1993b 1. Standard Fast (n = 35)



Maekawa 1993c 1. Apple Juice [10 ml/kg] 2 hrs preop (n = 35)



Meakin 1985a 1. Standard Fast (n = 20)

2. Orange squash [10 ml/kg max 200 ml] 2

hrs preop (n = 35)


Meakin 1985b 1. Standard Fast (n = 20)

2. Plain biscuits (x2) + Orange squash [10

ml/kg max 200 ml] 2 hrs preop (n = 32)

Yes Particles observed in gastric aspirate of 0

participants in fast group and 13 participants

permitted food and fluids up to 2 hrs preop.

Meakin 1985c 1. Orange squash [10 ml/kg max 200 ml] 2

hrs preop (n = 35)



participants in fluid group and 13 participants




Table 11. Details of Particles Observed in Gastric Aspirates (Continued )

Trial Comparison Observed Results


Meakin 1985d 1. Orange squash [10 ml/kg max 200 ml] 4

hrs preop (n = 15)




participants in fluid group and 3 participants


Meakin 1985e 1. Standard Fast (n = 20)

2. Orange squash [10 ml/kg max 200 ml] 4

hrs preop (n = 15)


Meakin 1985f 1. Standard Fast (n = 20)


ml/kg max 200 mls] 4 hrs preop (n = 14)

Yes Particles observed in gastric aspirate of

0 participants in fast group and and 3

participants permitted food and fluids up to 4

hrs preop.

Moyao-Garcia 2001 1. Standard Fast (n = 20)

2. Isosmolar solution of electrolytes [4 ml/kg]

3 hrs preop (n = 20)

Yes Results not reported

Splinter 1990a 1. Standard Fast (n = 31)

2. Apple Juice [6 ml/kg] 2.5 hrs preop (n =

30)


participants in fast group and 1 in fluid group.

This one participant had gastric volume of >

1 ml/kg.

Splinter 1990b 1. Standard Fast (n = 31)


32)


participants in fast group and 4 in fluid group.

All four participants had gastric volume of >

1 ml/kg.

Splinter 1990c 1. Apple Juice [6 ml/kg] 2.5 hrs preop (n =

30)


32)


participant in group permitted 6 ml/kg and 4

participants in group permitted 10 ml/kg. All

five had gastric volumes of > 1 ml/kg

Splinter 1991 1. Standard Fast (n=76)

2. Clear fluids [unlimited] up to 3 hrs preop

(n=76)

Yes Results not reported

Splinter Schaefer 2 1. Standard Fast (n = 64)

2. Clear Fluids [unlimited] up to 3 hrs preop

(n = 57)

Yes Particles observed in gastric aspirate of two

participants in fast and fluid groups.

Splinter Schaefer 3a/b/c 1. Clear fluids [unlimited] 3 hrs preop (n =

50)

2. Clear fluids [unlimited] 2.5 hrs preop (n =

50)

3. Clear fluids [unlimited] 2 hrs preop (n =

50)

Yes Milk curds observed in gastric aspirate of 5 of

36 participants who ingested bottled formula

milk (permitted up to 6 hrs preop) prior

to clear fluid interventions . No particles

observed in gastric aspirate of 8 participants

who ingested breast milk (permitted up to 4

hours preop).



Table 12. Duration of Fast - Aspiration/Regurgitation

Trial Method Measure Comparison Result

SHORTENED FLUID FAST versus STANDARD FAST

Fluids up to 120 mins preoperatively

Goresky 1992a reported adverse event, coughing,

aspiration

1. Standard Fast + placebo (n =

60)

2. Apple juice [5 ml/kg] +

placebo 2 hrs preop (n = 60)

8 spat out or vomited treatment

agent (unclear which group).

1 experienced flushing and

sweating after intervention

(possibly vaso-vagal reponse).

1 coughing regurgitation and

aspiration on induction (65

ml apple juice, no H2RA

intervention, 190 mins preop).

Authors suggest related to

airway management.

Goresky 1992b reported adverse event, coughing,

aspiration

1. Standard Fast + Ranitidine

[2 mg/kg] (n = 60)


Ranitidine [2 mg/kg] 2 hrs

preop (n = 60)

8 spat out or vomited treatment

agent (unclear which group).

One experienced flushing and


(possibly vaso-vagal response).

Maekawa 1993a unclear coughing; laryngospasm. 1. Standard Fast (n = 35)

2. Apple Juice [10 ml/kg] 2 hrs

preop (n = 35)

All inductions uneventful. No

coughing or laryngospasm

noted.

Meakin 1987a noted regurgitation, aspiration,

related morbidity or mortality

1. Standard Fast (n = 20)

2. Orange squash [10 ml/kg

max 200 ml] 2 hrs preop (n =

35)

None observed

Nicolson 1992 unclear intra-operative anaesthetic

complications


2. Clear fluids [unlimited] 2

hrs preop (n = 47)

None observed.

Schreiner 1990 noted present/absent 1. Standard Fast (n = 68)

2. Clear fluids [unlimited] up

to 2 hrs preop (n = 53)

No coughing or laryngospasm

or ’other complications’ noted.


Splinter 1989 noted regurgitation or aspiration 1. Standard Fast (n = 40)

2. Apple Juice [3 ml/kg] 2.5 hrs

preop (n = 40)

None observed

Splinter 1990a noted regurgitation or aspiration 1. Standard Fast (n = 31)


preop (n = 30)

None observed

Splinter 1990b noted regurgitation or aspiration 1. Standard Fast (n = 31)

2. Apple Juice [10 ml/kg] 2.5

hrs preop (n = 32)

None observed


Crawford 1990 noted aspiration pneumonitis 1. Water [2 ml/kg] 2 hrs preop None observed



Table 12. Duration of Fast - Aspiration/Regurgitation (Continued )


2. Water [2 ml/kg] 4 hrs preop

3. Water [2 ml/kg] 6 hrs preop

total n = 100

Gombar 1995 noted regurgitation, aspiration or

associated morbidity

1. Water (5 ml/kg) 3 hours

preop (n = 25)


None observed

Moyao-Garcia noted complication or adverse event 1. Standard Fast (n = 20)

2. Isosmolar solution of

electrolytes [4 ml/kg] 3 hrs

preop (n = 20)

None observed

Splinter Schaefer 2 noted regurgitation or aspiration 1. Standard Fast (n = 64)

2. Clear Fluids [unlimited] up


None observed

van der Walt 1986a noted regurgitation, aspiration,

associated morbidity or

mortality


2. Poly-joule (20%) [10 ml/kg]


No significant morbidity and

no mortality.

van der Walt 1986b noted regurgitation, aspiration,


mortality


2. Dextrose Solution (5%) [10

ml/kg] 3 hrs preop (n = 29)


no mortality.

van der Walt 1986c noted regurgitation, aspiration,


mortality


2. Cows’ milk [10 ml/kg] 3 hrs

preop (n = 31)


no mortality.

Up to 240 mins prep

Aun 1990 noted regurgitation at induction,

intraoperatively or during

recovery


2. Dextrose solution (5%) [10

ml/kg] 4hrs preop (n = 10)

None observed

Maekawa 1993b unclear coughing; laryngospasm;

vomiting.



preop (n = 35)


coughing, laryngospasm or

vomiting noted.

Meakin 1987e noted regurgitation, aspiration,





15)

None observed

SHORT SOLID + FLUID FAST versus STANDARD FAST

Meakin 1987b noted regurgitation, aspiration,



2. Plain biscuits (x2) + Orange

squash [10 ml/kg max 200 ml]

2hrs preop (n = 32)

None observed

Meakin 1987f noted regurgitation, aspiration,






None observed

SHORT SOLID + FLUID FAST versus SHORT FLUID FAST



Meakin 1987c noted regurgitation, aspiration,




34)



2hrs preop (n = 32)

None observed

Meakin 1987d noted regurgitation, aspiration,




15)




None observed

SHORT FLUID FAST 1 versus SHORT FLUID FAST 2

Cook-Sather 2003 unclear regurgitation, pulmonary

aspiration



2. Formula [unlimited] up to 4

hrs preop (n = 31)

None observed.

Maekawa 1993c unclear coughing, laryngospasm 1. Apple Juice [10 ml/kg] 2 hrs

preop (n = 35).


preop (n = 35).



noted.

Splinter Schaefer 1a noted regurgitation or aspiration 1. Clear Fluids [unlimited] up

to 3 hrs preop (n = 40) 2. Clear

Fluids [unlimited] up to 2.5

hrs preop (n = 40)

None observed.

Splinter Schaefer 1b noted regurgitation or aspiration 1. Clear Fluids [unlimited] up




None observed.

Table 13. Duration of Fast - Secondary Outcome Measures

Comparison Thirst Hunger Behaviour Comfort Nausea Vomiting

SHORTENED FLUID FAST versus STANDARD FAST


Goresky 1992a/b ˙ ˙ ˙ ˙ ˙ noted

Maekawa 1993a ˙ ˙ ˙ ˙ ˙ noted

Nicolson 1992 VAS VAS ˙ VAS ˙ ˙

Schreiner 1990 ˙ ˙ VAS VAS

Y/N/O (fluid group only)

˙ noted


Splinter 1989 VAS x 2 VAS x 2 ˙ ˙ ˙ ˙

Splinter 1990a/b VAS VAS VAS ˙ ˙ ˙




Table 13. Duration of Fast - Secondary Outcome Measures (Continued )


Gombar 1995 VAS ˙ VAS ˙ ˙ ˙

Splinter 1991 VAS VAS ˙ ˙ ˙ ˙


Aun 1990 ˙ ˙ ˙ ˙ ˙ noted

Maekawa 1993b ˙ ˙ ˙ ˙ ˙ noted

SHORT SOLID + FLUID FAST versus SHORT FLUID FAST

Kushikata 1996 ˙ 1-3 ˙ ˙ ˙ ˙

SHORTENED FLUID FAST 1 versus SHORTENED FLUID FAST 2

Cook-Sather 2003 ˙ LAS LAS ˙ ˙ noted

Maekawa 1993c ˙ ˙ ˙ ˙ ˙ noted

Table 14. Shortened Fluid Fast versus Standard Fast - Thirst

Trial Measurement Time of Measurement Comparison Result


Nicolson 1992 VAS [p] (g) 1. Clear fluids [unlimited +

mandatory] (n = 40 parents)

2. Standard Fast (NPO 4-8 hrs

dependent on age) (n = 40 parents)

Children permitted shorter fluid

fast were reported to be less thirsty

than the children in the standard

fasted group (p = 0.0001).


Splinter 1989 VAS [p]

VAS [c]

(f ) 1. Standard Fast (n = 40)


preop (n = 40)

Parents reported the children

permitted fluids were less thirsty

than those that remained fasted (p

< 0.05). No difference between the

children’s report. Three children

(< 5 years) unable to complete

questionnaire but it is unclear

which group they belonged to.

Splinter 1990a VAS [c] (f ) 1. Standard Fast (n = 31)


preop (n = 30)

Children in the fluid group

reported less thirst than those in

the group that followed a standard

fast. Two children (< 5 years)

unable to complete questionnaire -

unclear which group they belonged

to.

Splinter 1990b VAS [c] (f ) 1. Standard Fast (n = 31)


preop (n = 32)

No difference between groups.

Two children (< 5 years) unable to

complete questionnaire - unclear





Table 14. Shortened Fluid Fast versus Standard Fast - Thirst (Continued )


Gombar 1995 VAS [c] (f ) 1. Water [5 ml/kg] (n = 25)


Children in fluid group described

less thirst than those in standard

fast group (p < 0.1).

Splinter 1991 VAS [c] (f ) 1. Standard Fast (n = 76) 2. Clear

Fluids [unlimited] (n = 76)

Clear Fluids group recorded lower

thirst scores than the Standard Fast

group (p < 0.05).

Table 15. Shortened Fluid Fast versus Standard Fast - Hunger



Nicolson 1992 VAS [p] (g) 1. Clear fluids [unlimited] (n =

40 parents)

2. Standard Fast (n = 40 parents)

Children permitted shorter fluid

fast were reported to be less

hungry than the children in the

standard fasted group (p = 0.002).


Splinter 1989 VAS [p] VAS [c] (f ) 1. Clear apple juice [3 ml/kg] (n =

40 parents n = ? children)

2. Standard Fast (n = 40 parents n

= ? children)

Parents and children reported less

hunger amongst those permitted

fluids than those that remained

fasted (both p < 0.05). Three

children (< 5 years) unable to

complete questionnaire but it

is unclear which group they

belonged to.

Splinter 1990a VAS [c] (f ) 1. Clear apple juice [6 ml/kg] (n =

30?)

2. Standard Fast (n = 31?)

No difference between the groups

ratings of hunger. Two children

(< 5 years) unable to answer

questionnaire (unclear which

groups they belonged to).

Splinter 1990b VAS [c] (f ) 1. Clear apple juice [10 ml/kg] (n

= 32?)













Table 16. Shortened Fluid Fast versus Standard Fast - Behaviour



Schreiner 1990 VAS [p] Irritable (g) 1. Clear fluids [unlimited with

final ingestion up to 8 oz] (n =

45 parents)

2. Standard Fast (n = 50

parents)

Parents described children in

fluid group as less irritable

than those in the standard

fasting group (p < 0.001).

Splinter 1990a VAS [p] Upset/Irritable (f ) 1. Clear apple juice [6 ml/kg]

(n = 30 parents)


parents)

Children observed to be less

upset and irritable in fluid

group than in standard fasting

group (p < 0.05).

Splinter 1990b VAS [p] Upset/Irritable (f ) 1. Clear apple juice [10 ml/kg]

(n = 32 parents)


parents)



Gombar 1997 VAS [p] Irritable (f ) 1. Water [5 ml/kg] (n = 25)


Parents of children permitted

fluids reported their children

less irritable than those that

continued fasting (p > 0.01).

Table 17. Shortened Fluid Fast versus Standard Fast - Comfort



Nicolson 1992 VAS [p] Comfort (g) 1. Clear fluids [unlimited +


2. Standard Fast (NPO 4-8

hrs dependent on age) (n =

40 parents)

Children permitted shorter

fluid fast were reported to

be more comfortable in the

hour before being taken to

the operating room, than

the children in the standard


Schreiner 1990 VAS [p] Tolerance of preop

experience

Y/N/O [p fluid group]

Improved preop experience

(g) 1. Clear fluids [unlimited

with final ingestion up to 8

oz] (n = 45 parents)


parents)

Preoperative fasting

experience reported to be

tolerated better by the

children permitted fluids

than the children that

followed a standard fast (p <

0.01). Of the 18 children

who had prior experience

of the preoperative

procedures within the

hospital 14 parents reported

the shortened fluid fast

improved the experience for

their child, while the four



Table 17. Shortened Fluid Fast versus Standard Fast - Comfort (Continued )


remaining parents had no

opinion.

Table 18. Shortened Fluid Fast versus Standard Fast - Vomiting

Trial Method Measure Time of Measure Comparison Result


Goresky 1992a noted vomiting preoperative period 1. Standard Fast + placebo

(n = 60)



Children who vomited were

not distinguished from

those that gagged or spat

out intervention. Children’s

allocation to groups across

Goresky 1992a and Goresky

1992b unclear.

Goresky 1992b noted vomiting preoperative period 1. Standard Fast + Ranitidine

[2 mg/kg] (n = 60)



preop (n = 60)

Children who vomited were

not distinguished from

those that gagged or spat

out intervention. Children’s

allocation to groups across

Goresky 1992a and Goresky

1992b unclear.

Maekawa 1993a noted vomiting on induction 1. Standard Fast (n = 35)

2. Apple Juice [10 ml/kg] 2

hrs preop (n = 35)

None noted

Schreiner 1990 noted vomiting on induction 1. Standard Fast (n = 68)

2. Clear fluids [unlimited]

up to 2 hrs preop (n = 53)

None noted


Aun 1990 noted unclear on induction, intra-

operatively or recovery


2. Dextrose solution (5%)

[10 ml/kg] 4 hrs preop (n =

10)

None noted

Maekawa 1993b unclear vomiting on induction 1. Standard Fast (n = 35)

2. Apple Juice [10 ml/kg] 4

hrs preop (n = 35)

None noted

Table 19. Shortened Solid + Fluid Fast versus Short Fluid Fast - Hunger


Kushikata 1996 1-3 [c?] (e) 1. Standard Fast (n = 10)

2. Rice porridge [55 g rice + 245

ml water + some salt] 330 mins

preop + clear fluids [< 200 ml] up

Children in the group permitted

solid intake described less hunger

than those that fasted (p = 0.024).

It is unclear whether the hunger



Table 19. Shortened Solid + Fluid Fast versus Short Fluid Fast - Hunger (Continued )


to 5 hrs preop (n = 10) score was assigned by the child or

by the anaesthetist in response to

the child’s description.

Table 20. Short Fluid Fast 1 versus Short Fluid Fast 2 - Hunger

Trial Measure Time of Measurement Comparison Result

Cook-Sather 2003 VAS [p] (g) 1. Clear fluids [unlimited] up to 2

hrs (n = 36)

2. Formula [unlimited] up to 4 hrs

pre op (n = 31)


Table 21. Short Fluid Fast 1 versus Short Fluid Fast 2 - Behaviour


Cook-Sather 2003 VAS [p] Irritable (g) 1. Clear fluids [unlimited] up to

2 hrs (n = 36)

2. Formula [unlimited] up to 4

hrs pre op (n = 31)


Table 22. Short Fluid Fast 1 versus Short Fluid Fast 2 - Vomiting

Trial Method Measure Time of Measurement Comparison Result

Cook-Sather 2003 noted 1. Clear fluids [unlimited] up to 2

hrs (n = 36)

2. Formula [unlimited] up to 4 hrs

pre op (n = 31)

None reported

Maekawa 1993c noted vomiting on induction 1. Apple Juice [10 ml/kg] 2 hrs

preop (n = 35).


preop (n = 35).

None noted

Table 23. Type of Intake - Aspiration/Regurgitation


WATER versus STANDARD FAST




preop (n = 25)


None observed

CLEAR FLUIDS versus STANDARD FAST







complications

1. Standard Fast (n = 44) 2.

Clear fluids [unlimited] 2 hrs

preop (n = 47)

None observed.






None observed

FRUIT JUICE versus STANDARD FAST


aspiration


60)











airway management.

Goresky 1992b reported adverse event, coughing,

aspiration

1. Standard Fast + Ranitidine

[2 mg/kg] (n = 60)



preop (n = 60)




Maekawa 1993a unclear coughing; laryngospasm. 1. Standard Fast (n = 35)


preop (n = 35)



noted.

Maekawa 1993b unclear coughing; laryngospasm. 1. Standard Fast (n = 35)


preop (n = 35)



vomiting noted.



preop (n = 40)

None observed



preop (n = 30)

None observed



hrs preop (n = 32)

None observed

MILK v STANDARD FAST



mortality


2. Cows’ milk [10 ml/kg] 3 hrs

preop (n = 31)


no mortality.

DEXTROSE SOLUTION v STANDARD FAST



recovery



ml/kg] 4 hrs preop (n=10)

None observed



mortality





no mortality.

OTHER FLUIDS v STANDARD FAST





None observed



Table 23. Type of Intake - Aspiration/Regurgitation (Continued )



35)






15)

None observed

Moyao-Garcia noted complication or adverse event 1. Standard Fast (n = 20)



preop (n = 20)

None observed



mortality





no mortality.

FLUID 1 [F1] v FLUID 1 [F2]

van der Walt 1986d noted regurgitation, aspiration,


mortality

1. Dextrose (5%) [10ml/kg]

3hrs preop (n = 29)

2. Poly-joule (20%) [10ml/kg]

3hrs preop (n = 30)


no mortality.

van der Walt 1986e noted regurgitation, aspiration,


mortality

1. Dextrose (5%) [10ml/kg]

3hrs preop (n = 29)

2. Cows’ milk [10ml/kg] 3hrs

preop (n = 31)


no mortality.

van der Walt 1986f noted regurgitation, aspiration,


mortality

1. Poly-joule (20%) [10ml/kg]

3hrs preop (n = 30)

2. Cow’s milk [10ml/kg] 3hrs

preop (n = 31)


no mortality.

Table 24. Type of Intake - Secondary Outcome Measures


WATER versus STANDARD FAST




Schreiner 1990 ˙ ˙ VAS VAS Y/N/O (fluid group only) ˙ noted

Splinter Schaefer 2




Maekawa 1993a/b ˙ ˙ ˙ ˙ ˙ noted





OTHER FLUIDS versus STANDARD FAST

Aun 1990 ˙ ˙ ˙ ˙ ˙ noted

Table 25. Type of Fluid versus Standard Fast - Thirst





Children in water group described

less thirst than those in standard

fast group (p < 0.1).

Clear Fluids versus Standard Fast




hrs dependent on age) (n = 40

parents)

Children permitted clear fluids

were reported to be less thirsty





Clear Fluids group recorded lower

thirst scores than the Standard

Fast group (p < 0.05).



40?)



permitted apple juice were less

thirsty than those that remained

fasted (p < 0.05). No difference

between the children’s report.

Three children (< 5 years) unable

to complete questionnaire but

it is unclear which group they

belonged to.


30?)


Children in the apple juice group

reported less thirst than those in

the group that followed a standard

fast. Two children (< 5 years)

unable to complete questionnaire

- unclear which group they

belonged to.


= 32?)








Table 26. Type of Fluid versus Standard Fast - Hunger



Nicolson 1992 VAS [p] (g) 1. Clear fluids [unlimited] (n =

40 parents)


Children permitted clear fluids

were reported to be less hungry







Splinter 1989 VAS [p] VAS [c] (f ) 1. Standard Fast (n = 40)

2. Apple Juice [3 ml/kg] 2.5hrs

preop (n = 40)



apple juice than those that

remained fasted (both p < 0.05).

Three children (< 5 years) unable

to complete questionnaire but

it is unclear which group they

belonged to.



preop (n = 30)








preop (n = 32)






Table 27. Type of Fluid versus Standard Fast - Behaviour






water reported their children

less irritable than those that

continued fasting (p > 0.01).


Schreiner 1990 VAS [p] Irritable (g) 1. Clear fluids [unlimited -


45 parents)


parents)

Parents described children in

clear fluid group described as

less irritable than those in the

standard fasting group (p <

0.001).


Splinter 1990a VAS [p] Upset/Irritable (f ) 1. Clear apple juice [6 ml/kg] Children observed to be less



Table 27. Type of Fluid versus Standard Fast - Behaviour (Continued )


(n = 30 parents)


parents)

upset and irritable in apple

juice group than in standard

fasting group (p < 0.05).


(n = 32 parents)


parents)


Table 28. Type of Fluid versus Standard Fast - Comfort



Nicolson 1992 VAS [p] (g) 1. Clear fluids [unlimited]

(n = 40 parents)


parents)

Children permitted clear

fluids were reported to be

more comfortable in the

hour before being taken to

the operating room, than

the children in the standard


Schreiner 1990 VAS [p] Tolerance of

preoperative experience

Y/N/NoOpinion improved

overall experience as

reported by parents of

children in fluid group.





parents)




children permitted clear

fluids than the children that




of the preoperative







opinion.

Table 29. Type of Fluid versus Standard Fast - Vomiting



Schreiner 1990 noted present/absent on induction 1. Standard Fast (n = 68)



None noted




Table 29. Type of Fluid versus Standard Fast - Vomiting (Continued )



(n = 60)


placebo 2 hrs preop (n =

60)

Children who vomited

were not distinguished

from those that gagged or

spat out intervention (n =

8). Children’s allocation

to groups across Goresky

1992a and Goresky 1992b

unclear.

Goresky 1992b noted vomiting preoperative period 1. Standard Fast +

Ranitidine [2 mg/kg] (n =

60)


Ranitidine [2 mg/kg] 2hrs

preop (n = 60)



from those that gagged or

spat out intervention (n =

8). Children’s allocation

to groups across Goresky


unclear.


2. Apple Juice [10 ml/kg]


None noted




None noted

OTHER FLUIDS versus STANDARD FAST





[10 ml/kg] 4 hrs preop (n

= 10)

None noted

Table 30. Volume of Intake - Aspiration/Regurgitation

Trial Method Measure Comparison Results

LOW VOLUME FLUID INTAKE versus STANDARD FAST




preop (n = 25)


None observed


aspiration


60)











airway management.

Goresky 1992b reported adverse event, coughing, 1. Standard Fast + Ranitidine One experienced flushing and



Table 30. Volume of Intake - Aspiration/Regurgitation (Continued )


aspiration [2 mg/kg] (n = 60)



preop (n = 60)



Moyao-García 2001 noted complication or adverse event 1. Standard Fast (n = 20)



preop (n = 20)

None observed



preop (n = 40)

None observed

HIGH VOLUME FLUID INTAKE versus STANDARD FAST



recovery



ml/kg] 4 hrs preop (n=10)

None observed

Maekawa 1993a unclear coughing, laryngospasm 1. Standard Fast (n = 35)


preop (n = 35)



noted.

Maekawa 1993b unclear coughing, laryngospasm 1. Standard Fast (n = 35)


preop (n = 35)



vomiting noted.






35)

None observed






15)

None observed



preop (n = 30)

None observed



hrs preop (n = 32)

None observed



mortality





no mortality.



mortality





no mortality.




2. Cow’s milk [10 ml/kg] 3 hrs


no mortality.



Table 30. Volume of Intake - Aspiration/Regurgitation (Continued )


mortality preop (n = 31)

UNLIMITED FLUID INTAKE versus STANDARD FAST


complications

1. Standard Fast (n = 44) 2.

Clear fluids [unlimited] 2 hrs

preop (n = 47)

None observed.









None observed

VOLUME 1 [V1] versus VOLUME 1 [V]2]

Splinter 1990c noted regurgitation or aspiration 1. Apple Juice [6 ml/kg] 2.5 hrs

preop (n = 30)


hrs preop (n = 32)

None observed

Table 31. Volume of Intake - Secondary Outcome Measures


LOW VOLUME OF INTAKE versus STANDARD FAST




HIGH VOLUME OF INTAKE versus STANDARD FAST

Aun 1990 ˙ ˙ ˙ ˙ ˙ noted

Maekawa 1993a/b ˙ ˙ ˙ ˙ ˙ noted


UNLIMITED VOLUME OF INTAKE versus STANDARD FAST


Schreiner 1990 ˙ ˙ VAS VAS Y/N/O (fluid group only) ˙ noted


VOULME 1 [V1] versus VOLUME 2 [V2]

Splinter 1990c VAS VAS VAS ˙ ˙ ˙



Table 32. Volume of Fluid versus Standard Fast - Thirst


Low Volume of Intake versus Standard Fast



Children permitted low volumes

of fluid described less thirst than

those in standard fast group (p <

0.1).

Splinter 1989 VAS [p] VAS [c] (f ) 1. Standard Fast (n = 40)


preop (n = 40)


permitted a low volume of fluid

were less thirsty than those that

remained fasted (p < 0.05). No

difference between the children’s

report. Three children (< 5 years)


but it is unclear which group they

belonged to.

High Volume of Intake versus Standard Fast



preop (n = 30)

Children permitted a high volume

of fluid reported less thirst than

those in the group fasted. Two

children (< 5 years) unable to





preop (n = 32)





Unlimited Volume versus Standard Fast





parents)

Children permitted unlimited

fluids were reported to be less

thirsty than the children in

the standard fasted group (p =

0.0001).




fluids recorded lower thirst scores

than the group that fasted (p <

0.05).

Table 33. Volume of Fluid versus Standard Fast - Hunger




40 parents n = ? children)




a low volume of apple juice than

those that remained fasted (both p



Table 33. Volume of Fluid versus Standard Fast - Hunger (Continued )


< 0.05). Three children (< 5 years)


but it is unclear which group they

belonged to.



30?)








= 32?)












parents)


volumes of fluid intake were

reported to be less hungry than

the children in the standard fasted

group (p = 0.002).




Table 34. Volume of Fluid versus Standard Fast - Behaviour






a low volume of fluid reported

their children less irritable

than those that continued

fasting (p > 0.01).


Splinter 1990a VAS [p] Upset/Irritable (f ) 1. Clear apple juice [6 ml/kg]

(n = 30 parents)


parents)

Children observed to be less

upset and irritable in high

volume fluid group than in


0.05).


(n = 32 parents)


parents)





Schreiner 1990 VAS [p] Irritable (g) 1. Clear fluids [unlimited with


45 parents)


parents)

Children in unlimited fluid

group described as less

irritable than those in the


0.001).

Table 35. Volume of Fluid versus Standard Fast - Comfort






hrs dependent on age) (n =

40 parents)

Children permitted

unlimited fluid were

reported to be more

comfortable in the hour

before being taken to the

operating room, than the

children in the standard


Schreiner 1990 VAS [p] Tolerance of

preoperative experience

Y/N/NoO improved overall

experience as reported by

parents of children in fluid

group.





parents)




children permitted fluids

than the children that




of the preoperative







opinion.

Table 36. Volume of Fluid versus Standard Fast - Vomiting


Low Volume of Fluids versus Standard Fast


(n = 60)


placebo 2 hrs preop (n =

60)



from those that gagged

or spat out intervention.

Children’s allocation to

groups across Goresky


unclear.

Goresky 1992b noted vomiting preoperative period 1. Standard Fast +

Ranitidine [2mg/kg] (n =





Table 36. Volume of Fluid versus Standard Fast - Vomiting (Continued )


60)

2. Apple juice [5 ml/kg]

+ Ranitidine [2 mg/kg] 2

hrs preop (n = 60)

from those that gagged

or spat out intervention.

Children’s allocation to

groups across Goresky


unclear.

High Volume of Fluids versus Standard Fast





[10 ml/kg] 4 hrs preop (n

= 10)

None noted




None noted




None noted

Unlimited Volume of Fluids versus Standard Fast

Schreiner 1990 noted present/ absent on induction 1. Standard Fast (n = 68)



None noted

Table 37. Volume 1 [V1] versus Volume 2 [V2] - Thirst


Splinter 1990c VAS [c] (f ) 1. Apple Juice [6 ml/kg] 2.5 hrs preop (n =

30)


32)

No difference between groups. Two children

(< 5 years) unable to complete questionnaire

- unclear which group they belonged to.

Table 38. Volume 1 [V1] versus Volume 2 [V2] - Hunger


Splinter 1990c VAS [c] (f ) 1. Apple Juice [6 ml/kg] 2.5 hrs preop (n =

30)


32)

No difference between groups. Two children

(< 5 years) unable to complete questionnaire

- unclear which group they belonged to.



Table 39. Volume 1 [V1] versus Volume 2 [V2] - Behaviour


Splinter 1990c VAS [p] Upset/Irritable (f ) 1. Apple Juice [6 ml/kg] 2.5 hrs preop

(n = 30)


preop (n = 32)


Table 40. Sensitivitiy Analysis - excluding trials with inadequate randomisation

Comparison Outcome Subgroup Original WMD Exclusions WMD

01 Duration - Short

Fluid Fast versus

Standard Fast

02 Gastric Volume

(ml/kg)

01 Fluids (up to 120

minutes preop) versus

Standard Fast

WMD 0.03 95% CI

-0.03 to 0.10; NSD

WMD 0.03 95% CI

-0.07 to 0.12; NSD

05 Fluids (up to 240


Standard Fast

WMD 0.03 95% CI

-0.10 to 0.17; NSD

WMD 0.06 95% CI

-0.23 to 0.34; NSD

03 Gastric pH 01 Fluids (up to 120


Standard Fast

WMD 0.04 95% CI

-0.01 to 0.09; NSD

WMD -0.01 95% CI

-0.15 to 0.14; NSD

05 Type of Intake -

Fluid versus Standard

Fast

02 Gastric Volume

(ml/kg)

04 Fruit Juice versus

Standard Fast

WMD 0.02 95% CI

-0.08 to 0.11; NSD

WMD 0.04 95% CI

-0.10 to 0.17; NSD

07 Other Fluids versus

Standard Fast

WMD -0.13 95% CI

-0.41 to 0.16; NSD

WMD -0.38 95% CI

-0.58 to -0.19; (P <

0.0001)

03 Gastric pH 04 Fruit Juice versus

Standard Fast

WMD 0.04 95% CI

-0.01 to 0.10; NSD

WMD 0.07 95% CI

-0.08 to 0.22; NSD

07 Other Fluids versus

Standard Fast

WMD 0.34 95% CI

-0.62 to 1.31; NSD

WMD 0.42 95% CI

-1.92 to 2.77; NSD

07 Volume of Intake -

Volume of Fluid versus

Standard Fast

02 Gastric Volume

(ml/kg)

03 High Volume Fluid

Intake versus Standard

Fast

WMD 0.04 95% CI

-0.05 to 0.13; NSD

WMD 0.03 95% CI

-0.14 to 0.19; NSD

03 Gastric pH 03 High Volume Fluid

Intake versus Standard

Fast

WMD 0.04 95% CI

-0.02 to 0.09; NSD

WMD 0.00 95% CI

-0.18 to 0.19; NSD

WMD 0.00 95% CI

-0.18 to 0.19; NSD

G R A P H S

Comparison 01. Duration - Short Fluid Fast versus Standard Fast

Outcome titleNo. of

studies

No. of

participants Statistical method Effect size

02 Gastric contents - Volume

(ml/kg)

Weighted Mean Difference (Random) 95% CI Subtotals only

03 Gastric contents - pH Weighted Mean Difference (Random) 95% CI Subtotals only



04 Gastric contents - Phenol red

based volume (ml)


Comparison 02. Duration - Short Solid + Fluid Fast versus Standard Fast

Outcome titleNo. of

studies

No. of


02 Gastric Contents - Volume

(ml/kg)

Weighted Mean Difference (Fixed) 95% CI Subtotals only

03 Gastric Contents - pH Weighted Mean Difference (Fixed) 95% CI Subtotals only

Comparison 03. Duration - Short Solid + Fluid Fast versus Short Fluid Fast

Outcome titleNo. of

studies

No. of



(ml/kg)



Comparison 04. Duration - Short Fluid Fast 1 versus Short Fluid Fast 2

Outcome titleNo. of

studies

No. of



(ml/kg)


03 Gastric Contents - pH Weighted Mean Difference (Random) 95% CI Subtotals only

Comparison 05. Type of Intake - Fluid versus Standard Fast

Outcome titleNo. of

studies

No. of



(ml/kg)


03 Gastric contents - pH Weighted Mean Difference (Random) 95% CI Subtotals only

04 Gastric contents - Phenol red

based volume (ml)

1 44 Weighted Mean Difference (Fixed) 95% CI -3.10 [-6.66, 0.46]

Comparison 06. Type of Intake - Fluid 1 versus Fluid 2

Outcome titleNo. of

studies

No. of



(ml/kg)



Comparison 07. Volume of Intake - Volume of Fluid versus Standard Fast

Outcome titleNo. of

studies

No. of



(ml/kg)




03 Gastric contents - pH values Weighted Mean Difference (Random) 95% CI Subtotals only

Comparison 08. Volume of Intake - Volume 1 versus Volume 2

Outcome titleNo. of

studies

No. of



(ml/kg)


03 Gastric contents - pH Weighted Mean Difference (Fixed) 95% CI Subtotals only

I N D E X T E R M S

Medical Subject Headings (MeSH)

Adolescent; Child; Drinking; Fasting; Gastrointestinal Contents; Pneumonia, Aspiration [prevention & control]; Practice Guidelines;

Preoperative Care [methods]; Randomized Controlled Trials; Thirst; Time Factors

Medical MeSH check words

Humans

C O V E R S H E E T

Title Preoperative fasting for preventing perioperative complications in children

Authors Brady M, Kinn S, O’Rourke K, Randhawa N, Stuart P

Contribution of author(s) MB conducted the search, screened retrieved references for inclusion/exclusion, extracted

the data from included trials, evaluated methodological quality, contacted trial authors,

entered data, conducted data analysis, wrote the review.

SK participated in an initial literature search which led to the registration of a review title

with the Cochrane Collaboration and participated in the evaluation of the methodological

quality of the trials.

KO’R Developed a method of calculating suitable pseudo-values as an estimate of the

means and standard deviation summary data unavailable from the original publications.

This permitted representation of these trials within the meta-analysis. He also commented

on review drafts.

NR Provided statistical support for data extraction and data analysis.

PS participated in extracting the data from included trials and commented on review drafts.

Issue protocol first published 2001/1

Review first published 2005/2

Date of most recent amendment 10 February 2005

Date of most recent

SUBSTANTIVE amendment

10 February 2005

What’s New Information not supplied by author

Date new studies sought but

none found

Information not supplied by author

Date new studies found but not

yet included/excluded


Date new studies found and

included/excluded




Date authors’ conclusions

section amended


Contact address Marian Brady

Programme Leader

Nursing, Midwifery and Allied Health Professions Research Unit

Glasgow Caledonian University

Cowcaddens Road

Glasgow

G4 0BA

UK

E-mail: [email protected]

Tel: 0141 331 8102

DOI 10.1002/14651858.CD005285

Cochrane Library number CD005285

Editorial group Cochrane Wounds Group

Editorial group code HM-WOUNDS

G R A P H S A N D O T H E R T A B L E S

Fig. 1. Comparison 01. Duration - Short Fluid Fast versus Standard Fast

01.02 Gastric contents - Volume (ml/kg)

Review: Preoperative fasting for preventing perioperative complications in children

Comparison: 01 Duration - Short Fluid Fast versus Standard Fast

Outcome: 02 Gastric contents - Volume (ml/kg)

Study Short Fluid Fast Standard Fast Weighted Mean Difference (Random) Weight Weighted Mean Difference (Random)

N Mean(SD) N Mean(SD) 95% CI (%) 95% CI

01 Fluids (up to 120 minutes preop) versus Standard Fast (no H2-receptor antagonists)

Maekawa 1993a 35 0.39 (0.46) 35 0.36 (0.42) 9.4 0.03 [ -0.18, 0.24 ]

Meakin 1985a 35 0.37 (0.35) 20 0.21 (0.31) 12.2 0.16 [ -0.02, 0.34 ]

Nicolson 1992 44 0.60 (0.90) 47 0.40 (0.60) 4.2 0.20 [ -0.12, 0.52 ]

Sandhar 1989a 13 0.34 (0.30) 19 0.25 (0.30) 9.0 0.09 [ -0.12, 0.30 ]

Sarti 1991 32 0.44 (0.37) 30 0.38 (0.30) 13.8 0.06 [ -0.11, 0.23 ]

Schreiner 1990 48 0.44 (0.51) 67 0.57 (0.51) 11.1 -0.13 [ -0.32, 0.06 ]

Welborn 1993 41 0.08 (0.18) 43 0.08 (0.21) 40.3 0.00 [ -0.08, 0.08 ]

Subtotal (95% CI) 248 261 100.0 0.03 [ -0.03, 0.10 ]

Test for heterogeneity chi-square=6.82 df=6 p=0.34 I² =12.0%

Test for overall effect z=0.97 p=0.3

-1.0 -0.5 0 0.5 1.0

Fav Short Fluid Fast Fav Standard Fast (Continued . . . )



(. . . Continued)



02 Fluids (up to 120 minutes preop) versus Standard Fast (+ H2-receptor antagonists)

Sandhar 1989b 18 0.17 (0.20) 15 0.16 (0.18) 100.0 0.01 [ -0.12, 0.14 ]

Subtotal (95% CI) 18 15 100.0 0.01 [ -0.12, 0.14 ]

Test for heterogeneity: not applicable


03 Fluids (up to 150 minutes preop) versus Standard Fast

Splinter 1989 40 0.24 (0.31) 40 0.43 (0.46) 38.6 -0.19 [ -0.36, -0.02 ]

Splinter 1990a 30 0.66 (0.79) 16 0.45 (0.31) 30.3 0.21 [ -0.11, 0.53 ]

Splinter 1990b 32 0.71 (0.76) 15 0.45 (0.31) 31.1 0.26 [ -0.05, 0.57 ]

Subtotal (95% CI) 102 71 100.0 0.07 [ -0.25, 0.39 ]




Gombar 1997 25 0.34 (0.18) 25 0.38 (0.25) 20.2 -0.04 [ -0.16, 0.08 ]

Miller 1990 19 0.23 (0.21) 25 0.41 (0.34) 16.0 -0.18 [ -0.34, -0.02 ]

Moyao-García 2001 20 0.40 (0.29) 20 0.78 (0.44) 10.9 -0.38 [ -0.61, -0.15 ]

Splinter 1991 76 0.46 (0.39) 76 0.48 (0.40) 19.7 -0.02 [ -0.15, 0.11 ]

Splinter Schaefer 2 57 0.34 (0.28) 64 0.39 (0.37) 20.7 -0.05 [ -0.17, 0.07 ]

van der Walt 1986a 30 0.36 (0.33) 11 0.75 (0.67) 4.5 -0.39 [ -0.80, 0.02 ]

van der Walt 1986b 29 0.38 (0.37) 11 0.75 (0.67) 4.5 -0.37 [ -0.79, 0.05 ]

van der Walt 1986c 31 0.83 (0.80) 11 0.75 (0.67) 3.4 0.08 [ -0.41, 0.57 ]

Subtotal (95% CI) 287 243 100.0 -0.12 [ -0.22, -0.03 ]




Aun 1990 10 0.53 (1.00) 10 0.16 (0.15) 4.6 0.37 [ -0.26, 1.00 ]

Maekawa 1993b 35 0.35 (0.36) 35 0.36 (0.42) 53.6 -0.01 [ -0.19, 0.17 ]

Meakin 1985e 15 0.26 (0.31) 20 0.21 (0.31) 41.8 0.05 [ -0.16, 0.26 ]

Subtotal (95% CI) 60 65 100.0 0.03 [ -0.10, 0.17 ]



-1.0 -0.5 0 0.5 1.0

Fav Short Fluid Fast Fav Standard Fast




01.03 Gastric contents - pH



Outcome: 03 Gastric contents - pH



01 Fluids (up to 120 minutes preop) versus Standard Fast (no H2-receptor antagonists)

Goresky 1992a 48 1.96 (1.18) 51 1.94 (0.93) 1.5 0.02 [ -0.40, 0.44 ]

Maekawa 1993a 27 1.67 (0.65) 25 1.72 (0.48) 2.8 -0.05 [ -0.36, 0.26 ]

Meakin 1985a 31 2.14 (1.31) 14 1.85 (0.29) 1.1 0.29 [ -0.20, 0.78 ]

Nicolson 1992 20 1.90 (0.70) 17 2.00 (0.40) 2.0 -0.10 [ -0.46, 0.26 ]

Sandhar 1989a 12 1.83 (0.85) 10 2.10 (0.96) 0.4 -0.27 [ -1.04, 0.50 ]

Sarti 1991 32 1.70 (0.90) 30 1.60 (1.00) 1.2 0.10 [ -0.37, 0.57 ]

Schreiner 1990 35 1.82 (0.53) 48 1.77 (0.59) 4.5 0.05 [ -0.19, 0.29 ]

Welborn 1993 41 1.45 (0.07) 43 1.41 (0.17) 86.5 0.04 [ -0.02, 0.10 ]

Subtotal (95% CI) 246 238 100.0 0.04 [ -0.01, 0.09 ]



02 Fluids (up to 120 minutes preop) versus Standard Fast (+ H2-receptor antagonists)

Goresky 1992b 53 4.09 (2.26) 47 3.70 (2.33) 65.7 0.39 [ -0.51, 1.29 ]

Sandhar 1989b 15 4.76 (1.63) 14 3.97 (1.79) 34.3 0.79 [ -0.46, 2.04 ]

Subtotal (95% CI) 68 61 100.0 0.53 [ -0.20, 1.26 ]




Splinter 1989 40 2.20 (1.20) 40 1.70 (0.60) 31.4 0.50 [ 0.08, 0.92 ]

Splinter 1990a 30 1.70 (0.60) 16 1.70 (0.60) 36.7 0.00 [ -0.36, 0.36 ]

Splinter 1990b 32 1.80 (0.80) 15 1.70 (0.60) 31.9 0.10 [ -0.31, 0.51 ]

Subtotal (95% CI) 102 71 100.0 0.19 [ -0.11, 0.49 ]




Gombar 1997 24 2.53 (0.79) 25 2.26 (0.57) 17.8 0.27 [ -0.12, 0.66 ]

Miller 1990 19 1.70 (0.60) 25 1.60 (0.70) 17.8 0.10 [ -0.28, 0.48 ]

Moyao-García 2001 20 3.18 (0.61) 20 1.75 (0.38) 18.6 1.43 [ 1.12, 1.74 ]

-4.0 -2.0 0 2.0 4.0

Fav Standard Fast Fav Short Fluid Fast (Continued . . . )



(. . . Continued)



Splinter 1991 76 1.80 (1.00) 76 1.60 (0.40) 19.2 0.20 [ -0.04, 0.44 ]

Splinter Schaefer 2 57 1.80 (0.70) 64 1.70 (0.40) 19.5 0.10 [ -0.11, 0.31 ]

van der Walt 1986a 17 3.25 (1.57) 5 4.27 (2.69) 3.0 -1.02 [ -3.49, 1.45 ]

van der Walt 1986b 15 2.50 (0.89) 4 4.27 (2.94) 2.2 -1.77 [ -4.69, 1.15 ]

van der Walt 1986c 14 4.26 (2.42) 4 4.25 (2.90) 2.0 0.01 [ -3.10, 3.12 ]

Subtotal (95% CI) 242 223 100.0 0.32 [ -0.14, 0.78 ]

Test for heterogeneity chi-square=57.31 df=7 p=<0.0001 I² =87.8%



Maekawa 1993b 25 1.75 (0.61) 25 1.72 (0.48) 45.7 0.03 [ -0.27, 0.33 ]

Meakin 1985e 12 1.78 (0.42) 14 1.85 (0.28) 54.3 -0.07 [ -0.35, 0.21 ]

Subtotal (95% CI) 37 39 100.0 -0.02 [ -0.23, 0.18 ]



-4.0 -2.0 0 2.0 4.0

Fav Standard Fast Fav Short Fluid Fast


01.04 Gastric contents - Phenol red based volume (ml)



Outcome: 04 Gastric contents - Phenol red based volume (ml)




Miller 1990 19 6.30 (3.40) 25 9.40 (8.20) 100.0 -3.10 [ -6.66, 0.46 ]

Subtotal (95% CI) 19 25 100.0 -3.10 [ -6.66, 0.46 ]



-10.0 -5.0 0 5.0 10.0

Fav Short Fluid Fast Fav Standard Fast



Fig. 4. Comparison 02. Duration - Short Solid + Fluid Fast versus Standard Fast

02.02 Gastric Contents - Volume (ml/kg)


Comparison: 02 Duration - Short Solid + Fluid Fast versus Standard Fast

Outcome: 02 Gastric Contents - Volume (ml/kg)

Study Short Solid Fast Standard Fast Weighted Mean Difference (Fixed) Weight Weighted Mean Difference (Fixed)


01 Solids + Fluids (up to 120 minutes preop) versus Standard Fast

Meakin 1985b 32 0.46 (0.34) 20 0.21 (0.31) 100.0 0.25 [ 0.07, 0.43 ]

Subtotal (95% CI) 32 20 100.0 0.25 [ 0.07, 0.43 ]




Meakin 1985f 14 0.30 (0.30) 20 0.21 (0.31) 100.0 0.09 [ -0.12, 0.30 ]

Subtotal (95% CI) 14 20 100.0 0.09 [ -0.12, 0.30 ]



-1.0 -0.5 0 0.5 1.0

Fav Short Solid Fast Fav Standard Fast

Fig. 5. Comparison 02. Duration - Short Solid + Fluid Fast versus Standard Fast

02.03 Gastric Contents - pH


Comparison: 02 Duration - Short Solid + Fluid Fast versus Standard Fast

Outcome: 03 Gastric Contents - pH




Meakin 1985b 29 2.20 (1.11) 14 1.85 (0.28) 100.0 0.35 [ -0.08, 0.78 ]

Subtotal (95% CI) 29 14 100.0 0.35 [ -0.08, 0.78 ]




Meakin 1985f 10 1.96 (0.31) 14 1.85 (0.29) 100.0 0.11 [ -0.13, 0.35 ]

Subtotal (95% CI) 10 14 100.0 0.11 [ -0.13, 0.35 ]



-1.0 -0.5 0 0.5 1.0

Fav Standard Fast Fav Short Solid Fast



Fig. 6. Comparison 03. Duration - Short Solid + Fluid Fast versus Short Fluid Fast



Comparison: 03 Duration - Short Solid + Fluid Fast versus Short Fluid Fast


Study Short Solid Fast Short Fluid Fast Weighted Mean Difference (Fixed) Weight Weighted Mean Difference (Fixed)


01 Solids + Fluids versus Fluids (up to 120 minutes preop)

Meakin 1985c 32 0.46 (0.34) 35 0.37 (0.35) 100.0 0.09 [ -0.08, 0.26 ]

Subtotal (95% CI) 32 35 100.0 0.09 [ -0.08, 0.26 ]




Meakin 1985d 14 0.30 (0.30) 15 0.26 (0.31) 100.0 0.04 [ -0.18, 0.26 ]

Subtotal (95% CI) 14 15 100.0 0.04 [ -0.18, 0.26 ]




Kushikata 1996 10 0.55 (0.59) 10 0.43 (0.32) 100.0 0.12 [ -0.30, 0.54 ]

Subtotal (95% CI) 10 10 100.0 0.12 [ -0.30, 0.54 ]



-1.0 -0.5 0 0.5 1.0

Fav Short Solid Fast Fav Standard Fast



Fig. 7. Comparison 03. Duration - Short Solid + Fluid Fast versus Short Fluid Fast



Comparison: 03 Duration - Short Solid + Fluid Fast versus Short Fluid Fast





Meakin 1985c 29 2.20 (1.16) 31 2.14 (1.32) 100.0 0.06 [ -0.57, 0.69 ]

Subtotal (95% CI) 29 31 100.0 0.06 [ -0.57, 0.69 ]




Meakin 1985d 10 1.96 (0.31) 12 1.78 (0.42) 100.0 0.18 [ -0.13, 0.49 ]

Subtotal (95% CI) 10 12 100.0 0.18 [ -0.13, 0.49 ]




Kushikata 1996 10 1.89 (0.75) 10 1.43 (0.27) 100.0 0.46 [ -0.03, 0.95 ]

Subtotal (95% CI) 10 10 100.0 0.46 [ -0.03, 0.95 ]



-1.0 -0.5 0 0.5 1.0

Fav Standard Fast Fav Short Solid Fast



Fig. 8. Comparison 04. Duration - Short Fluid Fast 1 versus Short Fluid Fast 2



Comparison: 04 Duration - Short Fluid Fast 1 versus Short Fluid Fast 2


Study Shorter Fast Short Fast Weighted Mean Difference (Fixed) Weight Weighted Mean Difference (Fixed)


01 Fluids 120 minutes versus 150 minutes preop

Splinter Schaefer 3c 50 0.21 (0.37) 50 0.15 (0.14) 100.0 0.06 [ -0.05, 0.17 ]

Subtotal (95% CI) 50 50 100.0 0.06 [ -0.05, 0.17 ]




Splinter Schaefer 1b 74 0.33 (0.49) 74 0.27 (0.30) 77.7 0.06 [ -0.07, 0.19 ]

Splinter Schaefer 3a 50 0.21 (0.37) 50 0.25 (0.80) 22.3 -0.04 [ -0.28, 0.20 ]

Subtotal (95% CI) 124 124 100.0 0.04 [ -0.08, 0.15 ]




Cook-Sather 2003 36 0.16 (0.30) 31 0.19 (0.38) 57.7 -0.03 [ -0.20, 0.14 ]

Maekawa 1993c 35 0.39 (0.46) 35 0.35 (0.36) 42.3 0.04 [ -0.15, 0.23 ]

Subtotal (95% CI) 71 66 100.0 0.00 [ -0.13, 0.13 ]


Test for overall effect z=0.01 p=1


Splinter Schaefer 1a 40 0.37 (0.37) 40 0.38 (0.30) 69.9 -0.01 [ -0.16, 0.14 ]

Splinter Schaefer 3b 50 0.15 (0.14) 50 0.25 (0.80) 30.1 -0.10 [ -0.33, 0.13 ]

Subtotal (95% CI) 90 90 100.0 -0.04 [ -0.16, 0.09 ]



-1.0 -0.5 0 0.5 1.0

Fav Shorter Fast Fav Short Fast



Fig. 9. Comparison 04. Duration - Short Fluid Fast 1 versus Short Fluid Fast 2



Comparison: 04 Duration - Short Fluid Fast 1 versus Short Fluid Fast 2


Study Shorter Fluid Fast Short Fluid Fast Weighted Mean Difference (Random) Weight Weighted Mean Difference (Random)



Splinter Schaefer 3c 50 2.40 (1.30) 50 2.30 (1.30) 100.0 0.10 [ -0.41, 0.61 ]

Subtotal (95% CI) 50 50 100.0 0.10 [ -0.41, 0.61 ]




Splinter Schaefer 1b 74 1.80 (1.00) 74 1.90 (1.00) 55.4 -0.10 [ -0.42, 0.22 ]

Splinter Schaefer 3a 50 2.40 (1.30) 50 2.00 (1.00) 44.6 0.40 [ -0.05, 0.85 ]

Subtotal (95% CI) 124 124 100.0 0.12 [ -0.36, 0.61 ]




Cook-Sather 2003 36 2.90 (1.30) 31 2.50 (0.50) 44.7 0.40 [ -0.06, 0.86 ]

Maekawa 1993c 27 1.67 (0.65) 25 1.75 (0.61) 55.3 -0.08 [ -0.42, 0.26 ]

Subtotal (95% CI) 63 56 100.0 0.13 [ -0.33, 0.60 ]




Splinter Schaefer 1a 40 1.90 (1.00) 40 1.80 (0.90) 54.3 0.10 [ -0.32, 0.52 ]

Splinter Schaefer 3b 50 2.30 (1.30) 50 2.00 (1.00) 45.7 0.30 [ -0.15, 0.75 ]

Subtotal (95% CI) 90 90 100.0 0.19 [ -0.12, 0.50 ]



-1.0 -0.5 0 0.5 1.0

Fav Short Fluid Fast Fav Shorter Fast



Fig. 10. Comparison 05. Type of Intake - Fluid versus Standard Fast



Comparison: 05 Type of Intake - Fluid versus Standard Fast




01 Water versus Standard Fast

Gombar 1997 25 0.34 (0.18) 25 0.38 (0.25) 100.0 -0.04 [ -0.16, 0.08 ]

Subtotal (95% CI) 25 25 100.0 -0.04 [ -0.16, 0.08 ]



02 Clear Fluids versus Standard Fast

Nicolson 1992 44 0.60 (0.90) 47 0.40 (0.60) 5.1 0.20 [ -0.12, 0.52 ]

Sarti 1991 32 0.44 (0.37) 30 0.38 (0.30) 17.5 0.06 [ -0.11, 0.23 ]

Schreiner 1990 48 0.44 (0.51) 67 0.57 (0.51) 13.9 -0.13 [ -0.32, 0.06 ]

Splinter 1991 76 0.46 (0.39) 76 0.48 (0.40) 29.6 -0.02 [ -0.15, 0.11 ]


Subtotal (95% CI) 257 284 100.0 -0.02 [ -0.09, 0.05 ]



03 Dextrose Solution (5%) versus Standard Fast

Aun 1990 10 0.53 (0.91) 10 0.16 (0.15) 17.8 0.37 [ -0.20, 0.94 ]

Miller 1990 19 0.23 (0.21) 25 0.41 (0.34) 50.0 -0.18 [ -0.34, -0.02 ]

van der Walt 1986b 29 0.39 (0.36) 17 0.75 (0.67) 32.2 -0.36 [ -0.70, -0.02 ]

Subtotal (95% CI) 58 52 100.0 -0.14 [ -0.43, 0.15 ]



04 Fruit Juice versus Standard Fast (no H2-receptor antagonists)

Maekawa 1993a 35 0.39 (0.46) 18 0.36 (0.42) 11.0 0.03 [ -0.22, 0.28 ]

Maekawa 1993b 35 0.35 (0.36) 17 0.36 (0.42) 11.9 -0.01 [ -0.24, 0.22 ]

Sandhar 1989a 13 0.34 (0.30) 19 0.25 (0.30) 13.6 0.09 [ -0.12, 0.30 ]

Splinter 1989 40 0.24 (0.31) 40 0.43 (0.46) 17.5 -0.19 [ -0.36, -0.02 ]

Splinter 1990a 30 0.66 (0.79) 16 0.45 (0.31) 7.3 0.21 [ -0.11, 0.53 ]

Splinter 1990b 32 0.71 (0.76) 15 0.45 (0.31) 7.9 0.26 [ -0.05, 0.57 ]

Welborn 1993 41 0.08 (0.18) 43 0.08 (0.20) 30.9 0.00 [ -0.08, 0.08 ]

-1.0 -0.5 0 0.5 1.0

Fav Fluid Intake Fav Standard Fast (Continued . . . )



(. . . Continued)



Subtotal (95% CI) 226 168 100.0 0.02 [ -0.08, 0.11 ]



05 Fruit Juice versus Standard Fast (+ H2-receptor antagonists)

Sandhar 1989b 18 0.17 (0.19) 15 0.16 (0.17) 100.0 0.01 [ -0.11, 0.13 ]

Subtotal (95% CI) 18 15 100.0 0.01 [ -0.11, 0.13 ]



06 Milk versus Standard Fast

van der Walt 1986c 31 0.83 (0.80) 33 0.75 (0.72) 100.0 0.08 [ -0.29, 0.45 ]

Subtotal (95% CI) 31 33 100.0 0.08 [ -0.29, 0.45 ]



07 Other Fluids versus Standard Fast

Meakin 1985a 35 0.37 (0.35) 10 0.21 (0.31) 26.6 0.16 [ -0.06, 0.38 ]

Meakin 1985e 15 0.26 (0.31) 10 0.21 (0.31) 25.6 0.05 [ -0.20, 0.30 ]

Moyao-García 2001 20 0.40 (0.29) 20 0.78 (0.44) 26.3 -0.38 [ -0.61, -0.15 ]

van der Walt 1986a 30 0.36 (0.34) 16 0.75 (0.67) 21.5 -0.39 [ -0.74, -0.04 ]

Subtotal (95% CI) 100 56 100.0 -0.13 [ -0.41, 0.16 ]



-1.0 -0.5 0 0.5 1.0

Fav Fluid Intake Fav Standard Fast










01 Water versus Standard Fast

Gombar 1997 24 2.53 (0.79) 25 2.26 (0.57) 100.0 0.27 [ -0.12, 0.66 ]

Subtotal (95% CI) 24 25 100.0 0.27 [ -0.12, 0.66 ]



02 Clear Fluids versus Standard Fast

Nicolson 1992 20 1.90 (0.70) 17 2.00 (0.40) 11.0 -0.10 [ -0.46, 0.26 ]

Sarti 1991 32 1.70 (0.90) 30 1.60 (1.00) 6.4 0.10 [ -0.37, 0.57 ]

Schreiner 1990 35 1.82 (0.53) 48 1.77 (0.59) 24.5 0.05 [ -0.19, 0.29 ]

Splinter 1991 76 1.80 (1.00) 76 1.60 (0.40) 24.5 0.20 [ -0.04, 0.44 ]


Subtotal (95% CI) 220 235 100.0 0.09 [ -0.03, 0.21 ]




Miller 1990 19 1.70 (0.60) 25 1.60 (0.70) 66.8 0.10 [ -0.28, 0.48 ]

van der Walt 1986b 15 2.50 (0.88) 6 4.24 (2.60) 33.2 -1.74 [ -3.87, 0.39 ]

Subtotal (95% CI) 34 31 100.0 -0.51 [ -2.21, 1.19 ]



04 Fruit Juice versus Standard Fast (no H2-receptor antagonist)

Goresky 1992a 48 1.96 (1.18) 51 1.94 (0.93) 1.5 0.02 [ -0.40, 0.44 ]

Maekawa 1993a 27 1.67 (0.65) 13 1.72 (0.48) 2.1 -0.05 [ -0.41, 0.31 ]

Maekawa 1993b 25 1.75 (0.61) 12 1.72 (0.48) 2.1 0.03 [ -0.33, 0.39 ]

Sandhar 1989a 12 1.83 (0.80) 10 2.10 (0.93) 0.5 -0.27 [ -1.00, 0.46 ]

Splinter 1989 40 2.20 (1.20) 40 1.70 (0.60) 1.6 0.50 [ 0.08, 0.92 ]

Splinter 1990a 30 1.70 (0.60) 15 1.70 (0.60) 1.9 0.00 [ -0.37, 0.37 ]

Splinter 1990b 32 1.80 (0.80) 16 1.70 (0.60) 1.7 0.10 [ -0.30, 0.50 ]

Welborn 1993 41 1.45 (0.07) 43 1.41 (0.17) 88.6 0.04 [ -0.02, 0.10 ]

-4.0 -2.0 0 2.0 4.0

Fav Standard Fast Fav Fluid Intake (Continued . . . )



(. . . Continued)



Subtotal (95% CI) 255 200 100.0 0.04 [ -0.01, 0.10 ]



05 Fruit Juice versus Standard Fast (+H2- receptor antagonist)

Goresky 1992b 53 4.09 (2.26) 47 3.70 (2.33) 64.7 0.39 [ -0.51, 1.29 ]

Sandhar 1989b 15 4.76 (1.64) 14 3.97 (1.71) 35.3 0.79 [ -0.43, 2.01 ]

Subtotal (95% CI) 68 61 100.0 0.53 [ -0.19, 1.26 ]



06 Milk versus Standard Fast

van der Walt 1986c 14 4.24 (2.43) 13 4.25 (2.38) 100.0 -0.01 [ -1.82, 1.80 ]

Subtotal (95% CI) 14 13 100.0 -0.01 [ -1.82, 1.80 ]


Test for overall effect z=0.01 p=1

07 Other Fluids versus Standard Fast

Meakin 1985a 31 2.15 (1.33) 7 1.87 (0.35) 27.9 0.28 [ -0.26, 0.82 ]

Meakin 1985e 12 1.78 (0.42) 7 1.87 (0.35) 29.3 -0.09 [ -0.44, 0.26 ]

Moyao-García 2001 20 3.18 (0.61) 20 1.75 (0.38) 29.6 1.43 [ 1.12, 1.74 ]

van der Walt 1986a 17 3.25 (1.56) 7 4.25 (2.51) 13.2 -1.00 [ -3.00, 1.00 ]

Subtotal (95% CI) 80 41 100.0 0.34 [ -0.62, 1.31 ]



-4.0 -2.0 0 2.0 4.0

Fav Standard Fast Fav Fluid Intake




05.04 Gastric contents - Phenol red based volume (ml)



Outcome: 04 Gastric contents - Phenol red based volume (ml)

Study Treatment Control Weighted Mean Difference (Fixed) Weight Weighted Mean Difference (Fixed)



Miller 1990 19 6.30 (3.40) 25 9.40 (8.20) 100.0 -3.10 [ -6.66, 0.46 ]

Total (95% CI) 19 25 100.0 -3.10 [ -6.66, 0.46 ]



-10.0 -5.0 0 5.0 10.0

Favours treatment Favours control

Fig. 13. Comparison 06. Type of Intake - Fluid 1 versus Fluid 2



Comparison: 06 Type of Intake - Fluid 1 versus Fluid 2


Study Fluid 1 Fluid 2 Weighted Mean Difference (Fixed) Weight Weighted Mean Difference (Fixed)


01 Dextrose versus Poly-joule

van der Walt 1986d 29 0.39 (0.36) 30 0.36 (0.33) 100.0 0.03 [ -0.15, 0.21 ]

Subtotal (95% CI) 29 30 100.0 0.03 [ -0.15, 0.21 ]



02 Dextrose versus Cows’ milk

van der Walt 1986e 29 0.39 (0.36) 31 0.83 (0.79) 100.0 -0.44 [ -0.75, -0.13 ]

Subtotal (95% CI) 29 31 100.0 -0.44 [ -0.75, -0.13 ]



03 Poly-joule versus Cows’ Milk

van der Walt 1986f 30 0.36 (0.34) 31 0.83 (0.81) 100.0 -0.47 [ -0.78, -0.16 ]

Subtotal (95% CI) 30 31 100.0 -0.47 [ -0.78, -0.16 ]



-1.0 -0.5 0 0.5 1.0

Favours Fluid 1 Favours Fluid 2



Fig. 14. Comparison 06. Type of Intake - Fluid 1 versus Fluid 2



Comparison: 06 Type of Intake - Fluid 1 versus Fluid 2


Study Fluid 1 Fluid 2 Weighted Mean Difference (Fixed) Weight Weighted Mean Difference (Fixed)


01 Dextrose versus Polyjoule

van der Walt 1986d 15 2.50 (0.88) 17 3.25 (1.58) 100.0 -0.75 [ -1.62, 0.12 ]

Subtotal (95% CI) 15 17 100.0 -0.75 [ -1.62, 0.12 ]



02 Dextrose versus Cows’ milk

van der Walt 1986e 15 2.50 (0.89) 14 4.24 (2.43) 100.0 -1.74 [ -3.09, -0.39 ]

Subtotal (95% CI) 15 14 100.0 -1.74 [ -3.09, -0.39 ]



03 Poly-Joule versus Cows’ Milk

van der Walt 1986f 17 3.25 (1.56) 14 4.26 (2.45) 100.0 -1.01 [ -2.49, 0.47 ]

Subtotal (95% CI) 17 14 100.0 -1.01 [ -2.49, 0.47 ]



-4.0 -2.0 0 2.0 4.0




Fig. 15. Comparison 07. Volume of Intake - Volume of Fluid versus Standard Fast



Comparison: 07 Volume of Intake - Volume of Fluid versus Standard Fast


Study Fluid Intake Standard Fast Weighted Mean Difference (Random) Weight Weighted Mean Difference (Random)


01 Low Volume Fluid Intake versus Standard Fast

Gombar 1997 25 0.34 (0.18) 25 0.38 (0.25) 29.9 -0.04 [ -0.16, 0.08 ]

Moyao-García 2001 20 0.40 (0.29) 20 0.78 (0.44) 21.2 -0.38 [ -0.61, -0.15 ]

Sandhar 1989a 13 0.34 (0.29) 19 0.25 (0.30) 23.0 0.09 [ -0.12, 0.30 ]

Splinter 1989 40 0.24 (0.31) 40 0.43 (0.46) 25.8 -0.19 [ -0.36, -0.02 ]

Subtotal (95% CI) 98 104 100.0 -0.12 [ -0.29, 0.05 ]



02 Low Volume Fluid Intake versus Standard Fast (+H2-receptor antagonists)

Sandhar 1989b 18 0.17 (0.18) 15 0.16 (0.17) 100.0 0.01 [ -0.11, 0.13 ]

Subtotal (95% CI) 18 15 100.0 0.01 [ -0.11, 0.13 ]



03 High Volume Fluid Intake versus Standard Fast

Aun 1990 10 0.53 (0.88) 10 0.16 (0.16) 2.5 0.37 [ -0.18, 0.92 ]

Maekawa 1993a 35 0.39 (0.46) 18 0.36 (0.42) 10.1 0.03 [ -0.22, 0.28 ]

Maekawa 1993b 35 0.35 (0.36) 17 0.36 (0.42) 11.0 -0.01 [ -0.24, 0.22 ]

Meakin 1985a 35 0.37 (0.35) 10 0.21 (0.31) 11.5 0.16 [ -0.06, 0.38 ]

Meakin 1985e 15 0.26 (0.31) 10 0.21 (0.31) 10.0 0.05 [ -0.20, 0.30 ]

Splinter 1990a 30 0.66 (0.79) 16 0.45 (0.31) 6.7 0.21 [ -0.11, 0.53 ]

Splinter 1990b 32 0.71 (0.76) 15 0.45 (0.31) 7.2 0.26 [ -0.05, 0.57 ]

Welborn 1993 41 0.08 (0.18) 43 0.07 (0.19) 29.2 0.01 [ -0.07, 0.09 ]

van der Walt 1986a 30 0.36 (0.34) 11 0.75 (0.67) 4.3 -0.39 [ -0.80, 0.02 ]

van der Walt 1986b 29 0.39 (0.37) 11 0.75 (0.67) 4.2 -0.36 [ -0.78, 0.06 ]

van der Walt 1986c 31 0.83 (0.80) 11 0.75 (0.66) 3.3 0.08 [ -0.40, 0.56 ]

Subtotal (95% CI) 323 172 100.0 0.04 [ -0.05, 0.13 ]



-1.0 -0.5 0 0.5 1.0

Fav Fluid Intake Fav Standard Fast (Continued . . . )



(. . . Continued)



05 Unlimited Fluid Intake versus Standard Fast

Nicolson 1992 44 0.60 (0.90) 47 0.40 (0.60) 5.1 0.20 [ -0.12, 0.52 ]

Sarti 1991 32 0.44 (0.37) 30 0.38 (0.30) 17.5 0.06 [ -0.11, 0.23 ]

Schreiner 1990 48 0.44 (0.51) 67 0.57 (0.51) 13.9 -0.13 [ -0.32, 0.06 ]

Splinter 1991 76 0.46 (0.39) 76 0.48 (0.40) 29.6 -0.02 [ -0.15, 0.11 ]


Subtotal (95% CI) 257 284 100.0 -0.02 [ -0.09, 0.05 ]



-1.0 -0.5 0 0.5 1.0

Fav Fluid Intake Fav Standard Fast

Fig. 16. Comparison 07. Volume of Intake - Volume of Fluid versus Standard Fast

07.03 Gastric contents - pH values


Comparison: 07 Volume of Intake - Volume of Fluid versus Standard Fast

Outcome: 03 Gastric contents - pH values



01 Low Volume Fluid Intake versus Standard Fast

Gombar 1997 24 2.53 (0.79) 25 2.26 (0.57) 20.8 0.27 [ -0.12, 0.66 ]

Goresky 1992a 48 1.96 (1.18) 51 1.94 (0.93) 20.5 0.02 [ -0.40, 0.44 ]

Moyao-García 2001 20 3.18 (0.61) 20 1.75 (0.38) 21.4 1.43 [ 1.12, 1.74 ]

Sandhar 1989a 12 1.83 (0.84) 10 2.10 (0.96) 16.8 -0.27 [ -1.03, 0.49 ]

Splinter 1989 40 2.20 (1.20) 40 1.70 (0.60) 20.5 0.50 [ 0.08, 0.92 ]

Subtotal (95% CI) 144 146 100.0 0.42 [ -0.19, 1.04 ]



02 Low Volume Fluid Intake versus Standard Fast (+H2-receptor antagonists)

Goresky 1992b 53 4.09 (2.26) 47 3.70 (2.33) 63.9 0.39 [ -0.51, 1.29 ]

Sandhar 1989b 15 4.76 (1.60) 14 3.97 (1.69) 36.1 0.79 [ -0.41, 1.99 ]

Subtotal (95% CI) 68 61 100.0 0.53 [ -0.19, 1.26 ]


-4.0 -2.0 0 2.0 4.0

Fav Standard Fast Fav Fluid Intake (Continued . . . )



(. . . Continued)




03 High Volume Fluid Intake versus Standard Fast

Maekawa 1993a 27 1.67 (0.65) 13 1.72 (0.48) 2.1 -0.05 [ -0.41, 0.31 ]

Maekawa 1993b 25 1.75 (0.61) 12 1.72 (0.48) 2.1 0.03 [ -0.33, 0.39 ]

Meakin 1985a 31 2.15 (1.30) 7 1.87 (0.35) 1.0 0.28 [ -0.25, 0.81 ]

Meakin 1985e 12 1.78 (0.42) 7 1.88 (0.35) 2.2 -0.10 [ -0.45, 0.25 ]

Splinter 1990a 30 1.70 (0.60) 16 1.70 (0.60) 2.0 0.00 [ -0.36, 0.36 ]

Splinter 1990b 32 1.80 (0.80) 15 1.70 (0.60) 1.6 0.10 [ -0.31, 0.51 ]

Welborn 1993 41 1.45 (0.07) 43 1.41 (0.17) 88.9 0.04 [ -0.02, 0.10 ]

van der Walt 1986a 17 3.25 (1.57) 5 4.25 (2.71) 0.0 -1.00 [ -3.49, 1.49 ]

van der Walt 1986b 15 2.50 (0.89) 4 4.24 (2.90) 0.0 -1.74 [ -4.62, 1.14 ]

van der Walt 1986c 14 4.25 (2.44) 4 4.25 (2.92) 0.0 0.00 [ -3.13, 3.13 ]

Subtotal (95% CI) 244 126 100.0 0.04 [ -0.02, 0.09 ]



05 Unlimited Fluid Intake versus Standard Fast

Nicolson 1992 20 1.90 (0.70) 17 2.00 (0.40) 11.0 -0.10 [ -0.46, 0.26 ]

Sarti 1991 32 1.70 (0.90) 30 1.60 (1.00) 6.4 0.10 [ -0.37, 0.57 ]

Schreiner 1990 35 1.82 (0.53) 48 1.77 (0.59) 24.5 0.05 [ -0.19, 0.29 ]

Splinter 1991 76 1.80 (1.00) 76 1.60 (0.40) 24.5 0.20 [ -0.04, 0.44 ]


Subtotal (95% CI) 220 235 100.0 0.09 [ -0.03, 0.21 ]



-4.0 -2.0 0 2.0 4.0

Fav Standard Fast Fav Fluid Intake



Fig. 17. Comparison 08. Volume of Intake - Volume 1 versus Volume 2



Comparison: 08 Volume of Intake - Volume 1 versus Volume 2


Study Volume 1 Volume 2 Weighted Mean Difference (Fixed) Weight Weighted Mean Difference (Fixed)


01 6 ml/kg versus 10 ml/kg of apple juice 150 minutes preop

Splinter 1990c 30 0.66 (0.79) 32 0.71 (0.76) 100.0 -0.05 [ -0.44, 0.34 ]

Subtotal (95% CI) 30 32 100.0 -0.05 [ -0.44, 0.34 ]



-1.0 -0.5 0 0.5 1.0


Fig. 18. Comparison 08. Volume of Intake - Volume 1 versus Volume 2



Comparison: 08 Volume of Intake - Volume 1 versus Volume 2


Study Volume 1 Volume 2 Weighted Mean Difference (Fixed) Weight Weighted Mean Difference (Fixed)


01 6 ml/kg versus 10 ml/kg of apple juice 150 minutes preop

Splinter 1990c 30 1.70 (0.60) 32 1.80 (0.80) 100.0 -0.10 [ -0.45, 0.25 ]

Subtotal (95% CI) 30 32 100.0 -0.10 [ -0.45, 0.25 ]



-1.0 -0.5 0 0.5 1.0




Preoperative fasting for preventing perioperative complications in children

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